SHARP-EATMAN
NATURE
PHOTOGRAPHY
ID GUIDE TO WILD BEES - NEW YORK
GREEN SWEAT BEES
Genus: Augochlora, Augochloropsis & Augochlorella
GREEN SWEAT BEES
Tribe Augochlorini
Genus: Augochlora, Augochlorella & Augochloropsis
The Greek prefix augochlor- means "intense gold- green." According to Charles D. Michener’s The Social Behavior of the Bees, the tribe Augochlorini consists of bees that are typically brilliant green -- but sometimes purple, blue, brassy, red or black. Augochlorini are found predominantly in Central and South America and number more than 40 genera and more than 660 species. Nonetheless, in most of the continental United States and Canada, there are only 3 genera, divided into approximately 30 species -- Augochlora, Augochlorella, and Augochloropsis.
Traits of Augochlorini. Bees of the tribe Augochlorini can be recognized by these characteristics, among others: they are iridescent and usually green; and they have kidney-shaped compound eyes that are notched on the inner margin. All Augochlorini also possess two minute traits , visible under high magnification: (1) the hind tibiae are shorter than the combined tarsal segments of the lower leg; and (2) the bee's fifth terga (upper abdomen segment) is notched.
Bees of the Augochlorini tribe are often solitary and gregarious, but they also range from communal to semi-social. They tend to build nests in soil or, less commonly, in rotted wood. Some form large aggregations, constructing ground nests in clumps linked together by underground passages or rootlets.
Genus identification. Bees of the three genera Augochlora, Augochlorella and Augochloropsis are often confused with one another. Augochloropsis are also often misidentified as Agapostemon, a genus of large green striped sweat bees featured in this guide's preceding section. Tips for differentiating among these genera are detailed here.
Augochlora vs. Augochorella:
Augochlora and Augochlorella can be best told apart by examining differences in the forewings, and in head and facial structure. The features below are illustrated in the accompanying photo strip.
(1) Size: Augochlora are typically about 8 mm long. Augochlorella, by contrast, can be as small as 5.5 mm. Augochlorella size varies by species: species of the eastern United States typically range between 5.5 and 7 mm. (Two species found in the western United States - S. pomoniella and A. neglectula - may be as large as 8-9 mm.) Accordingly, within the eastern United States, green sweat bees in the smaller range (5.5 - 6.5 mm) are probably Augochlorella; those in the larger range (8 mm and above) are more likely to be Augochlora.
(2) Forewings: On the Augochlora forewing, the tip of the marginal cell is blunt or somewhat rounded, and it is pulled away from the margin of the cell. On the Augochlorella forewing, the marginal cell's tip is pointed and lies along the edge of the wing.
(3) Cheek and Vertex: The bee's cheek is the area behind the compound eye. The vertex is the top of the bee's head, right behind the small eyes called ocelli. On the Augochlora, the cheek and vertex are both fairly broad. On an Augochlorella, the cheek and vertex are narrow.
(4) Facial structure of females: The part of a bee's lower face directly above the mandibles is called the clypeus. On Augochlora females, the "parocular area" -- the face part directly above the clypeus and edging the inner compound eyes -- intrudes downward into the clypeus. The female Augochlorella lacks this trait. This trait is difficult to capture in field photographs but, when visible, it is an excellent way to identify the female Augochlora with certainty.
(5) Mandibles of females: The mandibles of female Augochlora are bidentate -- that is, each side of the mandibles terminates in a tip that forks into two pointed teeth. (The teeth are close in size, although the upper tooth is somewhat shorter.) By contrast, Augochlorella mandibles are sometimes described as "mitten-shaped." The mandibles terminate in tips that are broadly rounded lobes. A second set of small, rounded teeth project thumblike just short of the tips.
(6) Nesting Behavior: Augochlora pura nest in wood, while North American Augochlorella nest in the ground. Thus, if you find green bees emerging from nest holes in the ground, you probably should rule out Augochlora -- and conversely, if you encounter a green iridescent bee nesting in a rotted log, it is likely to be an Augochlora and not Augochlorella. (Note that ground-dwelling green bees might also be Augochloropsis or Agapostemon.)
Augochloropsis vs. Augochlora & Augochlorella
All Augochloropsis of the continental United States and Canada belong to the subgenus Paraugochloropsis. Augochloropsis of this North American region can be distinguished from Augochlora and Augochlorella of the same region by these traits:
(1) Tegulae. Tegulae are the plates where the wings join the thorax. On all Augochloropsis, the tegulae are D-shaped and mostly iridescent green. By contrast, on Augochlora, the tegula are oval and brown; on Augochlorella, they are roughly oval and yellowish-brown or pinkish brown.
(2) Legs. All three bee genera have some upper leg segments that may be partly iridescent green. On Augochloropsis , however, all segments through the tibia (1st to 4th segments) are brilliant iridescent green on all six legs. In addition, on males, the basitarsus (the segment directly below the tibia) is white on all six legs. These leg attributes distinguish Augochloropsis from all Augochlora and Augochlorella.
The iridescence of Augochloropsis tegulae and legs can be perceived by the naked eye, and thus serve as an excellent means of identifying these bees in the field.
Other traits: These are a few subtler traits that help separate Augochloropsis from Augochlora and Augochlorella. (1) Abdomen shape: the Augochloropsis abdomen is fairly uniformly broad and round. This aids particularly in distinguishing male Augochloropsis from male Augochlora pura and male Augochlorella, which tend to have narrow abdomens. (2) Hind leg of female: the leg spur on the hind tibia of the female Augochloropsis is comb-like. (3) Sternum of male: On male Augochloropsis, the fourth segment of the sternum (S4) has a median point. Male Augochlora and Augochlorella lack this trait. (On male Augochlora, the apical rim of S4 is straight. On male Augochlorella, S4 is somewhat curved to markedly curved.)
Augochloropsis vs. Agapostemon
Augochloropsis run larger than Augochlora pura and regional Augochorella. Eastern Augochloropsis species tend to be predictably green rather than other iridescent colors, and to have light-green eyes mottled with black -- traits shared by female Agapostemon. For all of these reasons, within our area, Augochloropsis are often confused with the large green iridescent bees of the genus Agapostemon, shown in this guide's next section.
Male Agapostemon can be easily differentiated from Augochloropsis because the former have striped abdomens -- no Augochloropsis have this trait. Female Agapostemon sometimes have striped abdomens, but they are more often entirely green.
The following traits help determine whether a large green iridescent bee of our region is an Augochloropsis vs. a female Agapostemon:
(1) Size: Agapostemon are generally larger than Augochloropsis. Female Augochloropsis are typically 8-11 mm. Agapostemon of the eastern United States are typically 9-15 mm.
(2) Legs: As noted above, leg segments of Augochloropsis are iridescent green from the uppermost segment to the tibia. By contrast, the legs of female Agapostemon of the northeastern United States are mostly darkly-colored. The legs of male Agapostemon are yellow or mostly yellow.
(3) Face: Both male and female Augochloropsis have faces that are predominantly iridescent green, and black mandibles. By contrast, regional male Agapostemon have extensive yellow markings on the face. Females have mandibles that are muddy greenish-yellow at the base. Eyes: The eyes of Augochloropsis are distinctly kidney-shaped, with an indentation on the inner rim. On Agapostemon, the indentation on the rim is subtler, so that the eyes appear less kidney-shaped.
GENERAL TRAITS OF THE TRIBE AUGOCHLORINI
Augochlorini are brilliantly iridescent, usually green bees.
Augochlororini may be brilliant blue green --
Or golden green --
A female Augochlora pura
A female Augochlorella aurata
A female Augochloropsis
AUGOCHLORA OR AUGOCHLORELLA?
This photo strip shows the differences between Augochlora and Augochlorella green sweat bees.
This is a female Augochlora.
This is a female Augochlorella.
AUGOCHLOROPSIS
vs. Augochlora & Augochlorella
This photo strip describes ways to tell Augochlopsis from Augochlora and Augochlorella.
LEGS (Augochloropsis): This is a female Augochloropsis. All legs of Augocloropsis are iridescent green from the top segment down to the tibia (the 4th leg segment). This trait distinguishes them from all Augochlora and Augochlorella. (On female Augochloropsis, the lower leg segments are mostly dark with reddish feet.)
LEGS (Augochloropsis): This is a male Auchloropsis metallica. Its legs are iridescent green from the top segment through the tibia. The basitarsi on all legs are white. These combined traits distinguish the male Augochloropsis from male Augochlora and Augochlorella.
AUGOCHLOROPSIS
vs. Agapostemon
This is a male Agapostemon: male Agapostemon have striped abdomens, and legs that are mostly or partly yellow. These traits distinguish them from all regional Augochloropsis (as well as Augochlora and Augochlorella).
This is a female Agapostemon. Most female Agapostemon do not have striped abdomens. Instead, both their heads and bodies are predominantly iridescent green. Females have dark legs covered with fine hairs.
LEGS: This is a female Augochloropsis (Paraugochloropsis). Augochloropsis also have heads and bodies that are predominantly iridescent green. All regional Augochloropsis, however, have legs that are iridescent green from the top segment through the tibia. This trait separates them from all northeastern female Agapostemon.
Taxonomy of Augochlorini
(Green Sweat Bees)
Order: Hymenoptera
Family: Halictidae (Sweat Bees)
Subfamily: Halictinae
Tribe: Augochlorini
Species shown below:
Genus: Augochlora
Subgenus: Augochlora
Species: Augochlora pura
(Pure green sweat bee)
Genus: Augochlorella
Species: Augochlorella aurata
(Golden green sweat bee)
Genus: Augochloropsis
Subgenus: Paraugochloropsis
Species: Augochloropsis viridula
(Northeastern sweat bee)
GREEN SWEAT BEE SPECIES OF NEW YORK
Pure Green Sweat Bee
Augochlora pura
Size: 8 mm (female)
6-8 mm (male)
The pure green sweat bee (Augochlora pura) is the only species of its genus in the eastern United States. Augochlora pura are iridescent bees that typically have brilliant green heads, thoraxes, and abdomens. Some individual specimens may be golden-green, coppery, or coppery pink. Males and females have smoky-brown wings.
The upper legs of female and male Augochlora pura are partially dark iridescent green. On females, the third through fifth leg segments (femur, tibia and basitarsi) are predominantly brownish-black and partly covered with light-colored hairs. Females carry pollen on scopae located on their upper hind tibiae. On males, the tibiae and basitarsi are multicolored, with dark, red and reddish-yellow coloration. The lower tarsi of both males and females are reddish.
Augochlora heads are roughly hexagonal, with dark green compound eyes, black antennae and dark, brownish-black mandibles. On all Augochlora, the cheek and vertex are broad. (The cheek is located behind the compound eye, and the vertex is located on the top of the head, behind the three small simple eyes called ocelli). All female Augochlora have mandibles that terminate in two-toothed points. Males have simple mandibles that teminate in single points.
General traits that distinguish Augochlora pura from similar green sweat bees such as Augochlorella aurata (shown below) are detailed in the introduction to this guide page.
Behavior: Augochlora pura are solitary bees that prefer woodland areas and build nests under bark in rotting trees. They cobble their nests together using bits of dirt and debris found under the bark. The female in the accompanying photos was discovered racing in and out of tunnels and holes in a fallen log near a Rockefeller State Park trail. Dozens of other Augochlora pura nested around her in the same log, looking like living emeralds scurrying in and out of the bark.
Augochlora pura emerge in early spring in southern New York, feeding on pollen from blossoming maple trees. Pure green sweat bees become highly visible in Rockefeller State Park in May, pollinating spring wildflowers and the tree peonies in the park's Peony Monument garden. In the summer, the bees can be seen visiting orange butterfly milkweed, wild phlox, and goldenrod in sunny areas along park trails; mobbing the flowers of black locust trees in abutting woods; and gathering pollen from squash and garden flowers in Stone Barns' vegetable and flower gardens. Augochlora pura continue to pollinate the park's late-blooming asters and goldenrod through mid-fall.
BEST FIELD IDENTIFICATION TRAITS: Augochlora
Broad vertex & cheek
Oval brown tegulae
Marginal cell tip blunt or rounded
Legs largely brownish-black and hairy in female, multicolored in male
Mandibles of females forked, with two pointed tips
Dark green eyes
Found nesting in wood, such as rotted logs
Most likely to be confused w/ Augochlorella
A female Augochlora pura
An Augochlora pura emerging from under the bark of a fallen tree
A female Augochlora pura: pure green sweat bees have iridescent (usually green) heads, thoraxes and abdomens. Females' legs are largely brownish black. (The upper leg segments are somewhat iridescent.)
Lateral view of the thorax of a female Augochlora pura: note the wide cheek -- wider than the compound eye. (The cheek is the area behind the compound eye.)
Dorsal view of a female Augochlora pura.
Golden-green Sweat Bee
Augochlorella aurata
Size: 5.5-7 mm
Golden-green sweat bees (Augochlorella aurata) tend to be smaller than the other green sweat bees shown on this page. Despite their name, golden-green sweat bees show considerable variation in color - ranging from pure green to yellow-green to coppery pink. The bees' upper legs are partly iridescent. On females, the tibia and lower legs are brown and covered with hairs. On males, the tibia and lower legs are multicolored with brown, reddish-brown and and reddish yellow. The wings of males and females are glassy with reddish brown veins. The tegulae (plates where the wings meet the thorax) are roughly oval and yellowish-brown or pinkish brown.
Identifying Traits: The introduction to this guide page provides a detailed comparison of the minute traits of Augochlorella that distinguish them from Augochlora and Augochloropsis. The bees' generally smaller size and tendency to brilliant color variations can be helpful clues for identifying them in the field. Among others, two distinctive traits of this species include the head's narrow vertex, and the bee's forewing structure. The tip of the marginal cell of an Augochlorella aurata forewing is pointed and lies along the edge of the wing. The these traits are shown in the accompanying photo strips.
Behavior: Augochlorella aurata are broad generalist pollinators that visit a seemingly endless range of wildflowers. In southern New York, they are likely to be spotted foraging on dogbane, fleabane, mountain mint, wild roses, and goldenrod. Augochlorella are also common pollinators of crops, such as apples, caneberries, carrots, strawberries, tomatoes, and watermelons.
Augochlorella aurata nest in partly-bare areas of flat or gradually sloped ground. In his seminal work, The Social Behavior of the Bees, entomologist Charles D. Michener wrote extensively on the nesting behavior and life cycle of Augochlorella aurata (known then under the name Augochlorella striata). Michener noted the species' primitively eusocial behavior: they have a yearly life cycle split into spring and summer phases. In the first spring “foundress phase,” females bees work together to construct an underground nest and provision it for 6-8 male and female offspring. When the young emerge, the males leave the nest, never to return. The females remain in the nest as workers.
In the second phase, the original “foundress workers” cease working and the new workers take over and provision the nest for a second brood of 8-13 males and females called reproductives. When this second brood hatches in late summer, the males and females mate. The males die and the inseminated females overwinter. To stay warm, the females dig downward into the earth from the lowest parts of their nests. They emerge in spring to complete the colony’s life cycle.
Augochlorella aurata social behavior shows flexibility, however. The bees' nests are sometimes established by a single foundress that dies off during the worker phase, and which is replaced by a single “replacement queen” from the first brood. In such instances, orphaned colonies are considered “parasocial”. (Only colonies that retain the original queen throughout the second season are called “eusocial”.) Parasocial colonies allow for more diversity of genetic material in the hive.
Other Augochlorella species: Augochlorella aurata is the only Augochlorella species in New York and the majority of New England States. It appears in all states of the continental United States except for Arizona and California.
Six other Augochlorella species occur in the continental United States and Canada: Augochlorella bracteata, A. gratiosa, A. karankawa, A. neglectula, A. persimilis, and A. pomoniella.
Augochlorella persimilis is widespread in much of the eastern United States south of New England. Augochlorella gratiosa is found throughout the southeastern United States, from Maryland to Florida, and in Gulf states from Florida to Texas. Both species are distinguished from Augochlorella aurata by minute traits visible only under strong magnification, such as qualities of the propodeum (the body part located directly behind the thorax).
Augochlorella bracteata and A. neglectula are found predominantly in the Southwest and Texas. Augochlorella pomoniella is found in the Southwest and California. Augochlorella karankawa was first described in 2004 and has been documented only in Oklahoma and Texas.
A female Augochlorella aurata
A male Augochlorella aurata
This is a female Augochlorella aurata found in Florida. This species occurs throughout the eastern United States. It is the only Augochlorella species of New York.
Alternate view of the female Augochlorella aurata. The bee's legs are mostly darkly colored and hairy. (The upper leg segments are somewhat iridescent.)
Note the narrow cheek (narrower than the compound eye).
A male Augochlorella aurata
Dorsal view: note the narrow vertex. The trait distinguishes Augochlorella aurata from Autochlora pura. (The vertex is the top of the head behind the small eyes called ocelli.)
Lateral view of bee
BEST FIELD IDENTIFICATION TRAITS:
Augochlorella
Narrow vertex & cheek
Oval Brown Tegulae
Marginal cell tip pointed & flush with wing edge
Legs mostly dark and hairy in female, multicolored in male
Found nesting in ground
In the Northeastern United States, generally smaller than Augochlora & Augochloropsis
Most likely to be confused w/ Augochlora
Northeastern Sweat Bee
Augochloropsis viridula
Size: 9 mm (.35 in.)
Augochloropsis are beautiful, brilliantly iridescent bees. Their heads and bodies are a shimmering green or blue-green. On all Augochloropsis, the tegulae (plates where the wings join the thorax) are predominantly iridescent green and D-shaped.
All Augochloropsis of the United States and Canada belong to the subgenus Paraugochloropsis. On both males and female Augochloropsis (Paraugochloropsis), the upper legs are iridescent green from the coxae to the tibia (the lst to 4th segments). On females, the basitarsus (5th segment) on all six legs is dark-colored and covered with light and brownish hairs. On males the basitarsi are white on all six legs.
Both female and male Augochloropsis (Paraugochloropsis) have iridescent green faces without yellow markings. On female and male bees, the mandibles are black or darkly-colored. On males, the labrum (the face-part between the mandibles) is darkly colored. Both males and females have blackish brown antennae and light-green eyes mottled with black spots. The bees' iridescent tegulae and largely iridescent legs are visible to the naked eye and aid greatly in field identifications.
Augochloropsis (Paraugochloropsis) are generally somewhat larger than Augochlora pura and regional Augochlorella. The abdomens of Augochloropsis are broad and round, giving them a more robust appearance than either Augochlora or Augochlorella. General differences between Augochloropsis and other green metallic bees are summarized in the introductory section at the top of this page.
Behavior: Augochloropsis (Paraugochloropsis) are solitary bees that nest in the ground. They are generalist pollinators that visit a wide gamut of flowering plants and are key pollinators in maintaining wildflower diversity. They are also important pollinators of crops, among them blueberries, caneberries, melons and squash.
Species Identification: Augochloropsis are believed to have originated 16 million years ago and to have entered temperate North America 4 million years ago. Within the Western Hemisphere, there are now 4 subgenera and more than 140 species of Augochloropsis, most of them found in Central and South America. Only seven species are found within the continental United States and Canada.
As of now, the most up-to-date summary of the genus is a detailed review of midwestern Augochloropsis compiled in 2022 by entomologists Zachary Portman, Mike Ardusher, Ian Lane and Daniel Cariveau. Prior to this work, Augochloropsis metallica (the green metallic bee) was considered the chief Augochloropsis species of New York. This species was divided into several subspecies.
In 2022, Portman et al elevated those subspecies to species status, Among these was Augochloropsis viridula. Many northeastern Augochloropsis once labelled Augochloropsis metallica have now been reclassified as Augochloropsis viridula. In popular databases such as iNaturalist, this species goes by the inglorious common name "northeastern sweat bee" -- it deserves better, because this is a stunning bee.
Augochloropsis metallica vs. A. viridula:
Augochloropsis metallica, as now defined, and A. viridula, are very similar. They are separated by geography and by minute characteristics.
Augochloropsis metallica, which appears in popular databases under the common name "metallic epauletted sweat bee," has a southernly and midwestern distribution within the United States, ranging from the New Jersey Pine Barrens south to Florida and Texas, and as far west as Colorado and South Dakota. Sporadic sightings have been documented as far north as New England and as far south as Nuevo Leon, Mexico.
New York Augochloropsis formerly named A. metallica are now generally recognized as Augochloropsis viridula.
These two species are distinguished by these physical characteristics:
(1) Pale hairs T2: On A. metallica, the hairs on the rear rim of T2 (second terga / upper abdominal segment) are thickened and flattened on the top central portion of the rim, and arranged close together and like the teeth of a comb. To the naked eye, this makes the fringe of pale hairs of T2 look wider than the thin bands rimming the abdominal segments behind T2. (T1 has a wide fringe similar to that on T2, but this is often worn off in older specimens.) On A. viridula, by contrast, the fringes of white hair on the tergal segments are uniformly narrow. These differences are shown in the accompanying photo strip.
T2 surface: In addition, on A. metallica, T2 is densely pitted, while on A. viridula, the pits on T2 are more widely spaced (with 2-4 pit-lengths between them). This second trait is visible only under considerable magnification.
BEST FIELD IDENTIFICATION TRAITS:
Augochloropsis
Upper legs and tibiae iridescent green
Male has white lower legs
Tegulae D-shaped, large & iridescent green
Abdomen robust, broad and rounded
No yellow markings on face or legs
Found nesting in ground
Most likely to be confused w/ female Agapostemon
A female Augochloropsis (Paraugochloropsis)
An Augochloropsis (Paraugochloropsis) viridula male from New York
An Augochloropsis (Paraugochloropsis) metallica male from Texas
Augochloropsis (Paraugochloropsis) are bright iridescent green or blue-green bees.
On female bees, the leg segments on all four legs are iridescent green from the top segment to the tibia (the fourth leg segment). On females, the basitarsi (below the tibiae) are mostly dark and covered with hairs. The lowest tarsi are reddish.
This is a male Augochloropsis viridula (northeastern sweat bee). Males have iridescent green upper legs like females. Males' lower legs (basitarsi) are white on all six legs. The lowest tarsi are reddish.
FLORAL ASSOCIATIONS: Augochloropsis viridula
There is little organized data on the newly erected northeastern sweat bee (Augochloropsis viridula). Available, largely anecdotal, data suggests that Augochloropsis viridula is a broad generalist.
Since 2022, this species has appeared frequently on iNaturalist in association with small-flowered plants, among them mountain mint; Apiaceae such as dill, fennel and Queen Anne's lace; and Asteraceae such as goldenrod, dandelion, fleabane, romerillo and yarrow.
In describing the new species A. viridula, Portman et al. (2022) examined specimens that had been found in association with a diverse range of plants, among them caneberries, dogwood, false indigo, milkweeds, monarda, nightshades, sumac, sweet clover, wild geranium, wild roses and wild quinine. The Discover Life bee species guide and checklist notes that A. viridula is associated with bindweed.
RECOMMENDED REFERENCES - Augochlorini
Ascher, John S., & John Pickering. Species Descriptions and Keys for Augochlora, Augochloropsis and Augochlorella. Discover Life Bee Species Guide and World Checklist (Hymenoptera: Apidae: Anthophila). Discover Life.
Coelho, Beatriz W. T. 2004. A review of the bee genus Augochlorella (Hymenoptera: Halictidae: Augochlorini). Systematic Entomology 29: 282-323.
Eickwort, George C. 1969. A comparative morphological study and generic revision of the Augochlorine bees (Hymenoptera: Halictidae). The University of Kansas Science Bulletin 48: 326–524.
Engel, Michael S. 2000. Classification of the bee tribe Augochlorini (Hymenoptera: Halictidae). Bulletin of the American Museum of Natural History 250: 1–89.
Gonçalves, Rodrigo. 2016. A molecular and morphological phylogeny of the extant Augochlorini (Hymenoptera, Apoidea) with comments on implications for biogeography. Systematic Entomology 41(4): 700-712.
Michener, Charles D. 1974. The Social Behavior of the Bees: A Comparative Study. Belknap Press of Harvard University Press.
Michener Charles D. 2007. The Bees of the World. 2nd Ed. Johns Hopkins University Press, Baltimore, 953 pp.
Mitchell, Theodore B. 1960. Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.
Ordway Ellen. 1966. Systematics of the genus Augochlorella (Hymenoptera, Halictidae) North of Mexico. The University of Kansas Science Bulletin 56(16): 509-624.
Portman, Zachary, Mike Ardusher, Ian Lane & Daniel Cariveau. 2022. A review of the Augochloropsis (Hymenoptera, Halictidae) and keys to the shiny green Halictinae of the midwestern United States. ZooKeys 1130: 103-152.
Sandhouse, Grace A. 1937. The bees of the genera Augochlora, Augochloropsis, and Augochlorella (Hymenoptera; Apoidea) occurring in the United States. Journal of the Washington Academy of Sciences 27: 65–79.