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Reprinted with Permission from: R.J. Oram. 2018. Revision of the Genus Hylaeus Fabricius (Hymenoptera: Colletidae) in Canada. Master’s Thesis University of Regina
Diagnosis: Females of Hylaeus communis are similar to females of H. leptocephalus and H. annulatus. They can be distinguished from H. leptocephalus by the large uniformly spaced episternal punctures, with tesselate interspaces in H. communis, and the large irregularly spaced punctures, with shiny interspaces in H. wootoni. The species can be distinguished from H. annulatus by the large punctures on the episternum in H. communis, and the small punctures on the episternum in H. annulatus. Males of Hylaeus communis can be easily separated from other species by the reduced maculations on the corners of the clypeus.
Females: average face width = 1.58mm; average thorax length = 1.83mm; average intertegular width = 1.38mm; average forewing length = 3.99mm. (n=5) Black, except for yellow maculation on lower paraocular area which extends from just above malar area to level of antennal sockets; flagellum brown on the lower surface, lateral yellow maculations on pronotal collar (these well-separated medially, sometimes absent), apical 2/3 of pronotal lobes, fore tibiae on basal 1/4, mid tibia with basal dot, and hind tibia on basal 1/3, tegula and costal sclerite usually with a pale maculation, sometimes lacking; wings clear with brown veins, forewing with base of vein C pale
yellow.
Head: Scape straight, with sparse, shallow punctures covering the surface, F1–F9 quadrate and subequal in length, F10 slightly longer than broad; clypeus longer than broad, with sparse shallow punctures (i = 1–2pd) with interspaces striated; superclypeal
area with dense shallow punctures (i < 1pd) basally between antennal sockets, becoming sparse apically (i > 1pd) interpsaces straited throughout; upper paraocular area and frons with dense and coarse punctures (interspaces hardly visible); vertexal area weakly
elevated, with dense punctures (interspaces hardly visible); compound eyes with inner margin slightly converging below; facial fovea elongate, with lower margin at level of bend in the inner eye margin, extending to upper curve of eye, fovea separated from upper margin of compound eye by width of fovea; face with sparse, short pale hairs;
mandibles with no hair.
Thorax: Pronotal collar rounded anteriorly, with medial portion slightly thinner than lateral portions; mesoscutum with coarse and dense punctures (interspaces hardly visible); parapsidal line faint, about 3/4 the length of the tegula; scutellum with deep, course, punctures (i < 1pd) interspaces smooth; metanotum rugosopunctate;
mesepisternum with anterior and lateral faces rounded, punctures course and close (i <1pd), with interspaces smooth; metepisternum rugose; propodeum with basal area heavily rugose, width subequal to metanotum, divided from posterior surface with a strong carina, posterior surfaces rugulose, with oblique carina present, posterior surface separated from the lateral surface by a weak carina, lateral surface rugulose; fore coxae rounded. Mesoscutum and scutelum with short, dark simple hairs intermixed with long, erect dark hairs; metanotum with short, dark simple hairs medially, and elongate, white
branched hairs laterally; pleuron with sparse, short, erect white hairs; propodeum with short, flat, white branched hairs on posterior surface and lateral surfaces; foreleg with sparse, short white branched hairs on coxa, sparse, erect pale hairs on femur, dense,
golden hairs on tibia, long, pale hairs on basitarsus and mediotarsus; mid leg with sparse, short white branched hairs on coxa, sparse, erect pale hairs on femur, sparse, short, pale hairs on tibia, short, pale hairs on basitarsus and mediotarsus; hind leg with sparse, short
white branched hairs on coxa, sparse, erect pale hairs on femur, sparse, short, pale hairs on tibia, short, pale hairs on basitarsus and mediotarsus.
Abdomen: T1 surface with sparse, small, shallow punctures (i > 3pd), interspaces shiny, T2 –T3 with puncturing and sculpturing like T1, T3–T6 with small pits where flat, golden hairs arise. T6 with long golden hairs on apical half; S1–S5 smooth and impunctate, with small pits where short, flat, white hairs arise; S5 with a line of sparse long, golden hairs delimiting an apical golden crescent; S6 with long black hairs medially, and long, white hairs apically.
Males: average face width = 1.51mm; average thorax length = 1.87mm; average intertegular width = 1.15mm; average forewing length = 4.03mm. (n=5) Black, except for yellow maculations on clypeus (reduced at apical corners), supraclypeal area, sides of face with maculation covering lower paraocular area extending from malar area to well above antennal sockets, not separate from the eye, maculation truncate to
bifid at top; flagellum brown on the lower surface), fore tibiae with basal dot, hind tibia with maculation on basal 1/4, basitarsus with basal ¼ maculated; wings predominantly clear, and slightly brown, with brown veins, forewing with base of vein C pale yellow.
Head: Scape enlarged apically, the width 2x more than the flagellum, with sparse, shallow punctures covering surface (i = 1pd) interspaces smooth, F1–F2 broader than long F3–F11 longer than broad, about 1.5 times longer than F1; clypeus longer than broad with extremely shallow punctures (i > 2pd) and interspaces smooth; supraclypeal area long, over half the length of clypeus, with extremely shallow punctures (i > 2pd) and interspaces smooth; upper paraocular area and frons with punctures dense and coarse
(interspaces hardly visible); vertexal area weakly elevated, densely punctured (interspaces hardly visible); compound eyes with inner margin converging below; facial fovea extremely short and shallow, restricted to the apex of compound eye. Scape with long simple hairs, face with sparse, short pale hairs, with short erect pale hairs at the top of the vertexal area and apical edge of the clypeus; mandibles with short erect hairs.
Thorax: Pronotal collar rounded anteriorly, the width of the medial portion equal to lateral portions; mesoscutum with coarse and dense punctures (interspaces hardly visible); parapsidal line absent; scutellum with punctation similar to mesoscutumn; metanotum rugosopunctate; mesepisternum with anterior and lateral faces rounded,
punctures course and close (i < 1pd), with interspaces smooth; metepisternum with course, close punctures (interspaces hardly visible); propodeum with basal area heavily rugose, width subequal to metanotum, divided from posterior surface with a strong carina, posterior surfaces weakly rugulose, with oblique carina present, posterior surface separated from the lateral surface by a weak carina, lateral surface with course deep punctures apically, smooth basally; fore coxae rounded. Mesoscutum and scutellum with dense, erect, gold simple hairs, with scutelum intermixed with longer, erect, golden
simple hairs; metanotum with erect, golden hairs medially, with white, branched hairs laterally, subequal in length to simple hairs; pleuron with long, pale, simple hairs; propodeum with short, erect, white branched hairs; foreleg with sparse, short white branched hairs on coxa, sparse, erect pale hairs on femur, dense, golden hairs on tibia,
long, pale hairs on basitarsus and mediotarsus; mid leg with sparse, short white branched hairs on coxa, sparse, erect pale hairs on femur, sparse, short, pale hairs on tibia, short, pale hairs on basitarsus and mediotarsus; hind leg with sparse, short white branched hairs
on coxa, sparse, erect pale hairs on femur, sparse, short, pale hairs on tibia, short, pale hairs on basitarsus and mediotarsus.
Abdomen: T1–T3 surface with sparse, small, shallow punctures (i > 3pd), interspaces shiny, T1–T5 with small pits where flat, golden hairs arise, T6–T7 with small pits where short dark, erect hairs arise; S1–S6 smooth, with smooth and impunctate, with small pits
where short, flat, white hairs arise; S6 with short erect black hairs covering the apical half.
Extracted from: Martins, K.T. et al. 2017. Hylaeus communis (Hymenoptera: Colletidae), a new exotic bee for North America with generalist foraging and habitat preferences. Canadian Entomologist...published online
Identification
Hylaeus communis belongs to subgenus
Hylaeus, males of which are recognised in
North America by the combination of omaulus
rounded (as opposed to carinate in subgenus
Spatulariella); margins of interantennal elevation
nearly parallel between antennal sockets, terminating
on frons well above level of upper margins
of antennal sockets (as opposed to margins of
interantennal elevations sharply convergent
between antennal sockets and ending little, if any,
above upper margins of antennal sockets in subgenera
Metziella Michener, 1942, Paraprosopis
Popov, 1939, and Prosopis Fabricius, 1804);
apical lobes of S7 pectinate with four apical lobes,
apical process of eighth sternum bilobate (as
opposed to spatulate in Spatulariella or with apex
rounded or truncate in Prosopis); and scape often
broadened apically (but unlike in subgenus
Cephalylaeus Michener, 1942, in which it is not
much broader than long) and concave beneath
(Michener 2007).
Females of subgenus Hylaeus
found in North America can be recognised by
omaulus not carinate (carinate in Spatulariella);
gena conspicuously narrower than the eye; T1
polished with punctures fine and scattered and
without apicolateral patch of highly plumose,
appressed pale pubescence (punctures more conspicuous
and well defined in subgenera Paraprosopis
and T1 with a conspicuous apicolateral
setae patch in Prosopis); and first tergum facial
foveae ending nearer to inner eye margin than to
lateral ocellus (ending nearer to lateral ocellus in
subgenus Paraprosopis). With reference to Macek
et al. (2010), the Dathe (1980, 2000) keys to
Palearctic Hylaeus sensu stricto and Snelling�s
(1970) key to North American species, males and
females of H. communis can be shown to be distinctive
among European and North American
members of subgenus Hylaeus in possessing the
following unique combination of characters (Fig. 1).
Males. Yellow markings on clypeus reduced to
a variable extent, usually not extending to lateral
margins, so that the yellow of the clypeus forms
an isolated, longitudinal, I-shaped bar with
irregular borders, but with yellow covering at
least the centre third; supraclypeal mark often
restricted to a yellow patch, so the extension of
the interantennal elevation above the level of the
antennal sockets is less conspicuous than in
other species of the subgenus that have larger
supraclypeal markings; lateral face marks not
fully separated from eye margin but with pointed
median extension ending over antennal sockets;
scape sometimes spotted yellow and moderately
broad, with width greater than 0.5 times its
length; second flagellomere about as long as
broad; flagellum long and black; metatibiae
yellow on less than basal half; and sternum 8 not
widened apically and glabrous.
Females. Face relatively elongate and with eyes
strongly converging below; clypeus with punctures
distinct and rather uniformly distributed throughout
including basal half; lateral face marks angled
slightly inwards towards the antennae above and
transversally truncate beneath; fovea short; malar
space shorter than broad; pronotum mostly black,
with yellow spot on distal portion of pronotal
lobes; tegula with yellow spot; mesepisternum
sharply angulate but not carinate anteriorly; propodeum
with enclosure divided by strong transverse
carina, with dorsal surface of enclosure with
strongly elevated longitudinal ridges separating
smooth interspaces; tergite 1 polished with fine
punctures; subsequent tergites have finer, denser
punctures; abdomen (T1) without lateral fringes;
and range in head width and length between
1.5 and 1.6mm.
Challenges to identification. Males of
H. communis found to date in eastern North
America have been readily identified due to
their distinctive yellow facial markings, as the
reduction of markings on the clypeus laterally
and on the supraclypeal area result in three
separated yellow patches on the face. This is
unlike other species with which it might be
confused where the yellow markings on the
lower face are contiguous (H. saniculae
(Robertson, 1896), with more reduced facial
markings, has broad depressions on the upper
face and is otherwise unlike the much larger
H. communis). However, males of H. communis
in Europe often have more fully developed
yellow facial markings. Identification of such
individuals, if found in North America, would be
more challenging. They would most likely be
confused with the similarly sized H. annulatus,
another yellow-faced species of subgenus
Hylaeus (unlike consubgeneric H. leptocephalus,
which differs conspicuously in having white or
pale cream markings).
Hylaeus annulatus differs
from H. communis in having a broader scape
extensively marked with yellow laterally
Martins et al.(scape black or with small sublateral yellow spot
in H. communis) and a broader face with inner
eye margins less strongly convergent below.
Females of H. communis are more difficult to
identify, as they are similar to H. annulatus.
Noteworthy features of H. communis include the
longer face with inner eye margins more strongly
converging below, presence of a yellow spot on
the tegula (usually absent in H. annulatus and in
H. modestus modestus, a superficially similar
species of subgenus Prosopis). The clypeus in
H. communis is rather uniformly punctate
throughout whereas in H. annulatus only the
apical half has distinct, regular punctures.
The propodeal enclosure of H. communis has
the dorsal enclosure regularly striate whereas
that of H. annulatus is more irregularly rugose.
Both of these Hylaeus (Hylaeus) species differ
conspicuously in propodeal sculpture from
yellow-marked Hylaeus (Prosopis) species such
as H. modestus in that only the latter lacks the
strong transverse carina that delimits the dorsal
and posterior face of the propodeal enclosure in
the former.
Hylaeus leptocephalus females are
readily distinguished by the white rather than
yellow integumental markings and also differ in
other characters such as the duller sculpturing
of the mesepisternum.
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