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Agapostemon nasutus Smith, 1853
Agapostemon peruvianus Cameron, 1903; Agapostemon nasutus gualanicus Cockerell, 1912; Agapostemon purpureopictus Cockerell, 1924; Agapostemon melanurus Cockerell, 1949

Life   Insecta   Hymenoptera   Apoidea   Halictidae   Agapostemon
Subgenus: Notagapostemon

Agapostemon nasutus, male, head, mtg
© Kimberly Huntzinger, 2007 · 4
Agapostemon nasutus, male, head, mtg

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Identification
Extracted from: Roberts, 1972. The University of Kansas Science Bulletin. Agapostemon nasutus Smith 1853. Type $, British Museum (Natural History).
Agapostemon peruvianus Cameron 1903 (new synonymy). Type $, British Museum (Natural

History).
Agapostemon nasutus gualanicus Cockerell 1912a (new synonymy). Type $, U.S. National

Museum.
Agapostemon purpureopictus Cockerell 1924 (new synonymy). Type 9, California Academy

of Sciences, San Francisco.
Agapostemon melanurus Cockerell 1949 (new synonymy). Type 9. U.S. National Museum.

I have seen the types of all the above forms except A. nasutus and A.
peruvianus, which were examined for me by Michener. There is no doubt
that they are all the same species. A. nasutus gualanicus Cockerell is an
ill-defined geographic variant which does not seem to warrant formal
recognition as a subspecies (see discussion of variation).

Distribution (Fig. 7). Agapostemon nasutus is the most common and
widespread of the tropical Agapostemon. Absent from the central plateau of
Mexico, it occurs along the eastern coast as far north as Brownsville, Texas,
and along the western coast as far north as Hermosillo, Sonora, and El Arco,
Baja California. It is widespread in southern Mexico and Central America
but has not been found in the wet Atlantic lowlands of Nicaragua, Costa
Rica and Panama. It has been collected along the coast of Venezuela as far east as Trinidad, in the Cauca and Magdalena valleys of Colombia, and
west of the Andes as far south as lea, Peru.

It has been collected at or near sea level throughout its range and at
elevations as high as 8,500 ft. (2,591 m) at Calderon, Ecuador; 1,200 m
(3,963 ft.) at San Jose, Costa Rica; 5,000 ft. (1,524 m) at Guatemala City,
Guatemala; and 6,400 ft. (1,951 m) at Tecamachalco, Puebla, Mexico. It
has been collected in South America in every month but October, in Central
America in every month but December and in Mexico north of the Isthmus
of Tehuantepec in every month but January. Thus it seems that this species
flies most, if not all, of the year wherever it occurs. My field observations
in Costa Rica indicate that it is hard to find toward the end of the dry season,
when flowers are also scarce.

Diagnosis. Males are easily distinguished from all other species by the
unique "hog-nosed" appearance of the broad, concave, ventral portion of the
short clypeus (Figs. 85-87) and by sternum 6 which is broad with laterally
directed disto-lateral tufts of branched hairs usually visible from above.
Females, as well as males, may be distinguished from all other species with-
out acutely pointed lateral pronotal angles by a yellow or creamy spot at the
apex of the rounded posterior lobe of the pronotum (Fig. 134).

Variation. The females normally are metallic green on the head and
thorax but in the central highlands of Central America (e.g., Gualan,
Guatemala and San Jose, Costa Rica) the green is replaced by blue. This
is the form named A. nasutus gitalanicus by Cockerell. The same blue
color is also found in many females from the southern limits of the range
(e.g., Lima, Peru) and the northern limits of the range (e.g., Brownsville,
Texas and Hermosillo, Sonora) where it may be very dark purple-blue.

Normally black, the abdomen is pale amber in the majority of females
from coastal Venezuela. I have seen females with black or intermediate
abdomens from this same region although these constitute less than 10%
of the total sample (Fig. 7).

The amount of yellow on the males and females is quite variable and
is slightly correlated with the coloration of the head and mesosoma of females.
Blue females fly with males usually more extensively marked with black
or brown than are males from regions where the metallic color of the
females is green.

Description
male (Figs. 85-87, 153, 195, 221-223)

General coloration of head and mesosoma metallic green to blue-green
or bronze, metasoma yellow with black bands. Head (Figs. 85-87): (1)
Labrum yellow, 40% as long as broad, flattened basal area slightly concave,
20% as long as broad, distal area triangular, 85 % as long as basal width and
separated from it by sharp step. Distal area shiny, impunctate; basal area with scattered punctures most abundant distally. Distal margin with row
of about 32 widely separated bristles, stout medially, finer laterally, re-
mainder of distal area glabrous; basal area with scattered, prostrate hairs
directed distally, longest and most abundant distally and forming fringe
on distal margin of basal area. (2) Clypeus with ventral area smooth and
shiny, dorsal area shiny and coarsely punctate; flattened ventral area glabrous,
at right angle to upper area which is densely covered with white to yellowish
hairs. (3) Interocular area with dense, fine punctures below vertex, rugose
laterally, coarsely punctate or rugose above antennal sockets; pubescence
dense, white to yellowish hairs nearly as long as scape and much shorter
along inner margins of eyes. (4) Vertex with dense fine punctures below
and in ocellar triangle; coarsely and shallowly rugose behind ocellar triangle.
(5) Gena with sparse, weak carinulae extending postero-dorsally from antero-
ventral margin; pubescence dense, white (never yellowish), medially about
1.5 times as long as on interocular area. (6) Malar area yellow; pubescence
sparse, white, tomentose. (7) Mandible yellow with apical third transparent
ferruginous; nearly straight, not strongly curved as in other species. Pubes-
cence on flat outer surface and posterior margin white to yellowish and
directed apically; single longitudinal row of short simple bristles on inner
surface. (8) Antenna (except scape and last two flagellomeres) dark brown
above and light brown to yellow below; scape yellow with brown on apical
V4- 1 /? above; last flagellomere brown with pale spot on upper side at apex;
penultimate flagellomere brown, becoming yellow or light brown on basal
V2 of underside. Mesosoma: metallic green, blue-green or bronze, with
yellow or creamy spot on apex of posterior lobe of pronotum; moderately
dense, white or creamy pubescence evenly distributed on all but anterior
and lateral surfaces of pronotum. (9) Pronotum with lateral angle and
posterior lobe rounded; 2-4 inconspicuous parallel carinae slanting rearwards
and downwards near postero-lateral margin. Tomentum on lower lateral
area white. (10) Mesoscutum densely covered with moderately deep, con-
fluent punctures, fine posteriorly, becoming shallowly rugose on anterior
l A- l A- (H) Mesoscntellum with fine, moderately deep punctures separated
by about their own diameters. (12) Metanotum moderately and shallowly
rugose medially, rugulose laterally. (13) Mesepistermtm coarsely and shal-
lowly rugose anteriorly, becoming moderately rugose posteriorly. (14)
Metepistemum with weak, parallel, interconnected, horizontal carinulae.
(15) Propodeutn coarsely and shallowly rugose laterally, rugae slightly
coarser and deeper dorso-medially; propodeal carina weak, evenly rounded
dorsally; propodeal shield weakly and irregularly carinulate. (16) Wing
pale, transparent brown, not darkened apically, radius much darker than
other veins. (17) Tegula yellow with large transparent area in center of
posterior half and transparent on posterior, distal and anterior margins. (18) Fore leg yellow, sometimes with brown on posterior surface of coxa,
trochanter and base of femur. Pubescence on coxa, trochanter and basal l / 2
of femur sparse, long, white and branched; on tarsus, tibia and apex of
femur sparse, short, simple, white to yellowish. (19) Middle leg yellow, coxa
brown; trochanter and posterior area of femur sometimes brown; pubescence
like that of fore leg. (20) Hind leg (Fig. 153) with coxa brown, becoming
green dorsally; trochanter brown; brown streak on basal % of posterior
surface of femur; tibia and tarsus yellow; on some specimens with brown
on basal % of tibia and all but anterior of femur; pubescence similar to
that of preceding legs except posterior surfaces of basitarsus and femur
which are densely covered with short, stiff, simple, yellow hairs directed
distally. Metasoma: (21) Terga 1-6 transparent apically, each with
subapical brown or black band slightly broader than transparent area (may
seem broader if abdomen is flexed and brown basal band of underlying
tergum shows through overlapping transparent margin of preceding
tergum), central yellow band almost twice as wide as subapical black band,
and narrow brown or black basal band; tergum 1 with additional yellow
basal region; tergum 7 brown or black; pygidial plate fawn to yellow. Pu-
bescence fine and short dorsally, longer laterally, at base of tergum 1, and on
posterior margins of terga 5-7; white except on dark portions of terga 5-7
where yellow or brown; terga shiny with small, shallow punctures separated
by about their own diameters. (22) Sterna 2-5 yellow, each with subapical
brown band, apical margin transparent, narrow brown basal band often
concealed by overlap of preceding sternum but sometimes so broad as to
be confluent with subapical brown band; sternum 1 brown, tinged with
green basally, paler subapically, distal and lateral margins transparent;
sternum 6 yellow with basal brown band and transparent distal margin;
yellow areas on abdominal sterna sometimes partially or completely replaced
by brown; sternum 6 very broad with disto-lateral bulge and longitudinal
medial ridge; sternum 1 with few scattered long white hairs and thin
fringe of short hairs on distal margin; sterna 2-5 with scattered long yellow
hairs subapically, distal margins fringed with short, prostrate hairs, basal %
of each with minute, simple, white hairs; sternum 6 with numerous long
yellowish hairs conspicuously branched, short medially but with long disto-
lateral tufts directed postero-laterally and usually visible from above. (23)
Genitalia (Figs. 195, 221-223) far more complex than those of other species,
and relatively large.

female (Figs. 41-42, 134)

General coloration of head and thorax metallic green to blue. Metasoma

black or pale amber, with white bands of fine pubescence. Head (Figs.

41-42): pubescence short ( l / 2 J A as long as shortest distance between antennal

sockets) and white or yellowish on face, twice as long on gena and pure white. (1) Labrum dark amber to ferruginous. Basal ridge prominent,
proximal face sloping gently toward proximal margin, distal face sharply
declivous, and apex of ridge with deep punctures; distal portion narrow,
abruptly rounded at apex; conspicuous median keel on antero-distal portion,
continued basally almost to basal ridge; anterior margin of keel flattened
and slightly flared laterally; single row of dark amber, wide, flat, stiff
bristles curving anteriorly at their apices forming fimbria on lateral margins
of distal portion of labrum. (2) Clypeus green above with yellow band on
lower Yi-Yi bordered with black; yellow almost entirely replaced with dark
brown or black on darker specimens; median subapical area slightly concave,
yellow band with large scattered punctures, upper green area with numerous
short horizontal carinulae or horizontally elongate punctures. (3) Inter-
ocular area coarsely and shallowly rugose, supraclypeal protuberance with
dense, long, horizontal carinulae. (4) Vertex densely and finely punctate
between, anterior to, and lateral to ocelli; coarsely and shallowly rugose be-
hind ocelli. (5) Gena with numerous weak, contiguous rugulae running
postero-dorsally from antero-ventral margin. (6) Malar area brown and
very short. (7) Mandible yellow, apical Y 3 ferruginous. (8) Antenna
dark brown to black, slightly paler brown on underside of flagellum.
Mesosoma: pubescence (except on pronotum) nearly twice as long as
on face, moderately dense, white laterally and below, but may be yellowish
or fuliginous on mesoscutum and mesoscutellum of blue specimens. (9)
Pronotum (Fig. 134) with yellow to creamy spot at apex of posterior lobe;
lateral angle and posterior lobe rounded as in $ \ faint punctures on dorsal
portion and faint parallel striae running downward and rearward on lower
lateral area; pubescence white, very fine, short, and appressed on lower
lateral area. (10) Mesoscutum as in $ . (11) Mesoscutellum finely and
densely punctate anteriorly, becoming coarsely punctate posteriorly; shiny,
less densely punctate area lateral to center. (12) Metanotum rugulose. (13)
Mesepisternum coarsely rugose anteriorly, somewhat less coarsely so pos-
teriorly. (14) Metepisternum as in $ . (15) Propodeum coarsely rugose
dorsally and postero-laterally, becoming finely striate antero-ventrally;
propodeal carina prominent, strongly curved dorso-laterally, weakly convex
dorsally; propodeal shield with irregularly anastomosing carinulae running
laterally and slightly upward from mid-line. (16-17) Wing and tegula
as in $ .
(18) Fore leg brown to black with yellow on anterior apical % of femur and basal % of tibia, may be more extensive on pale specimens; pubescence of coxa, trochanter and femur white, becoming yellow on tibia and tarsus. (19) Middle leg similar in color and pubescence to fore leg but pubescence on dorsal surface of tibia and tarsus fuliginous. (20) Hind leg brown to black, pubescence similar to that of middle leg but even darker on dorsal surface of tibia and tarsus and with pale penicillus at apex of basitarsus. Metasoma: (21) Terga usually black but often pale amber with black at apices of terga 4-6 in Colombian and Venezuelan specimens; anterior vertical portion of tergum 1 with sparse white hairs, upper x /z w i m thin white tomentum; basal halves of terga 2-4 with dense white tomentum; prepygidial fimbria and hairs adjacent to pygidium and on apical portion of tergum 4 brown to black. (22) Sterna brown to black, often pale amber in Colombian and Venezuelan specimens; long, scattered, whitish pubescence on exposed portions.


Names
Scientific source:

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FamilyScientific name @ source (records)
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Convolvulaceae  Ipomoea carnea @ BBSL (7)
Malvaceae  Gossypium @ AMNH_BEE (2)
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