• Hosts

Diagnosis:
Females of Hylaeus affinis are similar to H. modestus and H. illinoisensis. They can be distinguished from H. modestus by the pleural punctures, which are deep and close with interspaces tesselate or rugulose in H. affinis, and shallow punctures with smooth interspaces more than one puncture diameter in H. modestus. Females of H. affinis can be distinguished from H. illinoisensis by the presence of small, but distinct punctures on the T1; T1 of H. illinoisensis is polished and impunctate. Males of H. affinis is similar to H. sparsus. They can be distinguished from H. sparsus by the fore coxa being rounded, and S7 having a truncate apical process in H. affinis and the fore coxa being angulate, and S7 having the apical process tapered in H. sparsus.

Females: average face width = 1.62mm; average thorax length = 1.77mm; average intertegular width = 1.21mm; average forewing length = 3.73mm. (n=5) 33 Black, except for pale yellow maculation on lower paraocular area which extends from just above malar area to level of antennal sockets, rarely slightly above; flagellum ferruginous on the lower surface, lateral yellow maculations on pronotal collar (these well-separated medially), apical half of pronotal lobes, fore and mid tibiae on basal 1/3, hind tibia on basal half, 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 slightly arched, with dense, shallow punctures covering the surface, F1 quadrate, F2 broader than long, about half the length of F1, F3–F9 quadrate and subequal in length to F1, F10 slightly longer than broad; clypeus as long as broad, with sparse shallow punctures on basal half (i > 2pd), interspaces shiny, deep grooves running vertically from basal to apical edges, apical half impunctate; superclypeal area with dense shallow punctures (i < 1pd) basally between antennal sockets, becoming sparser apically (i > 1pd); upper paraocular area and frons with dense and coarse punctures interspaces hardly visible); vertexal area slightly elevated, with dense punctures (interspaces hardly visible), punctures becoming more sparse (i > 2–3pd) around lateral ocellus and towards vertexal area; compound eyes with inner margin weakly 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, becoming slightly more divergent above (width of two fovea); face with sparse, short pale hairs, with short erect dark hairs at the top of the vertexal area and apical edge of the clypeus; mandibles with short erect hairs.

Thorax: Pronotal collar rounded anteriorly, width of collar even throughout; mesoscutum with coarse and dense punctures (i < 1 pd), interspaces tesselate; parapsidal lines faint, about the length of the tegula; scutellum with punctation similar to mesoscutum, but becoming more slightly sparser laterally (i = 1); metanotum with surface rugose; mesepisternum with anterior and lateral faces rounded, sculpturing variable, either rugosopunctate with shallow punctures evident between rugulae, or with variable puncture density with interspaces always i ≤ 1pd, with surface greatly tesselated; metepisternum rugosopunctate, with punctures evident between the rugulae; propodeum base heavily rugose, width subequal to metanotum, separated from posterior surface by weak carina becoming evanescent nearing the metanotum laterally, posterior surfaces rather smooth and weakly punctate in upper area, becoming slightly rugulose below, posterior surface rounded onto lateral surface, lateral surface tessellate, punctures shallow and dense (interspaces hardly visible); fore coxae rounded. Mesoscutum and scutellum with sparse short, flat, white simple hairs intermixed with short, erect dark hairs; metanotum with short, white hairs medially, with elongate, white branched hairs laterally; pleuron with elongate white hairs, about twice as long as those on mesoscutum; propodeum with short, white branched hairs at edge of posterior surface, with long, white branched hairs under the wing base on posterior and lateral surfaces; foreleg with a mixture of short and long white branched hairs on coxa, mixture of erect pale and dark hairs on femur, flattened pale hairs on tibia, long, sparse pale hairs on meditarsus and basitarsus; mid leg with short branched white hairs on coxa, mixture of short pale hairs and erect dark hairs on femur, short, flat pale hairs on tibia, long, sparse pale hairs on meditarsus and basitarsus; hind leg with short, semi-erect white hairs on coxa; with short, pale hairs throughout on remaining segments, with erect hairs intermixed on basitarsus.

Abdomen: T1with pale apical fasciae laterally, surface smooth and shiny, with small, widely spaced (i > 3pd) punctures medially, becoming closer (i < 1pd) laterally, T2 –T5 smooth and polished, with small pits from which short, fine pale white hairs arise, T6 smooth and polished, with long dark erect hairs arising from apical edge, T4 with apical edge with sparse, long white hairs, those on T5 dark; with sparse, long dark hairs; S1–S5 smooth, with small pits from which small fine plae white hairs arise, S6 smooth; S4 with sparse, long white hairs apically, S5 with sparse, simple black hairs, with a line of dense black hairs delimiting an apical golden crescent; S6 with long black hairs restricted to apex.

Males: average face width = 1.58mm; average thorax length = 1.61mm; average intertegular width = 1.26mm; average forewing length = 3.58mm. (n=5) Black, except for mandibles, labrum, clypeus, supraclypeal area, sides of face with maculation covering lower paraocular area extending from malar area to level of antennal sockets, not separate from the eye, maculation truncate at top, scape maculated on outer concave edge, flagellum ferruginous on the lower surface; lateral yellow maculations on pronotal collar (these well-separated medially), pronotal lobes extensively maculated, fore tibiae maculated in full dorsally, fore basitarsus and mediotarsus yellow, mid tibia with basal 1/3 maculated, with a small pale dot on apical edge, mid basitarsus and mediotarsus yellow, hind femur with a small basal dot on apical edge, tibia with maculation on basal half and a small band covering apical end, basitarsus and mediotarsus yellow, tegula with a small maculation medially, costal sclerite with a maculation on the outer edge; wings predominantly clear, and slightly brown, with brown veins, forewing with base of vein C pale yellow.

Head: Scape arched, with dense, shallow punctures covering surface, F1 and F2 quadrate, length subequal, F3–F10 longer than broad, subequal in length, F11 slightly longer than F3–F10; clypeus slightly longer than broad with sparse extremely shallow punctures (i >3pd) and interspaces smooth; supraclypeal area short, about half the length of clypeus, and impunctate; upper paraocular area and frons with punctures dense and coarse (interspaces hardly visible); vertexal area slightly elevated, densely punctured (interspaces hardly visible), punctures becoming more sparse (i > 1.5pd) around lateral ocellus and towards vertexal area; compound eyes with inner margin weakly converging below; facial fovea extremely short, localized at the upper edge of compound eye and slightly diverging towards the lateral ocellus; face with sparse, short pale hairs, with short erect dark hairs at the top of the vertexal area and apical edge of the clypeus; mandibles with short erect hairs; genal area with short white branched hairs.

Thorax: Pronotal collar rounded anteriorly, width of collar even throughout; mesoscutum with punctures coarse and dense (i < 1 pd), interspaces tesselate; parapsidal lines faint, short and have a round fovea shape on apical end; scutellum with course close punctures with interspaces nearly absent; metanotum with surface rugose;m mesepisternum with anterior and lateral faces rounded, sculpturing course with interspaces nearly absent; metepisternum rugosopunctate, with punctures evident between the rugulae; propodeum with basal area heavily rugose, width slightly longer than metanotum, separated from posterior surface by a strong carina, posterior surface rugose entirely, posterior surface rounded onto lateral surface, lateral surface with punctures shallow and dense (no interspaces), with tessellation occurring within the punctures; fore coxae rounded. Mesoscutum and scutellum with short, erect, dark simple hairs; metanotum with long, pale white hairs medially, with long, white, branched hairs laterally; pleuron with long, white, branched hairs; propodeum with short, white branched hairs at edge of posterior surface, with long, white branched hairs under the wing base on posterior and lateral surfaces; foreleg with long white branched hairs on coxa, mixture of erect pale and dark hairs on femur, flattened pale hairs on tibia, long, sparse pale hairs on tibia; mid leg with short simple hairs throughout, with erect hairs on the tarsi and basitarsi intermixed, hind leg with short, semi-erect white hairs on coxa; with short, pale hairs throughout on remaining segments, with erect hairs intermixed on basitarsus.

Abdomen: T1 with pale apical fasciae laterally, surface smooth and shiny, with small, widely spaced (i > 3pd) punctures medially, becoming closer (i < 1pd) laterally, T2 –T7 with small pits from which short, fine pale white hairs arise causing the surface to look roughened, T6 with dark erect simple hairs on lateral edges, T7 with dark hairs on lateral and apical edges; S1–S6 smooth, with small pits from which small fine pale white hairs arise, S1–2 with flat pale simple hairs, S3–7 with spars, long, white hairs throughout.

Reprinted with permission from: Mitchell, T.B. 1960 Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.


FEMALE�Length 5-6 mm.; black; antennae piceous above, brownish beneath; face marks yellow, triangular, entirely filling area between clypeus and eyes, terminated more or less acutely close to eye margin slightly above antennae; collar with a pair of conspicuous transverse maculae; tubercles and an anterior spot on tegulae yellow, tegulae otherwise ferruginous; wings subhyaline, veins and stigma ferruginous; legs black, with basal third or more of all tibiae yellow; spurs pale yellow; face slightly narrowed below; cheeks and eyes subequal in width in lateral view; foveae deep, distinct, linear and rather long, separated from eye by a slightly wider space, rather markedly divergent from eye above; 2nd and 3rd segments of flagellum broader than long, length and breadth subequal on basal and other segments; front coxae simple; dorsal surface of propodeum sloping, shorter than metanotum, coarsely reticulate, posterior surface more finely reticulate, not carinate laterally, lateral surfaces obscurely punctate below, becoming densely and finely rugose above; metanotum densely and finely rugose; clypeus tessellate. with sparse, very fine and obscure punctures; face above antennae closely, deeply and distinctly punctate; punctures of scutum deep and distinct, close but not crowded, those of scutellum slightly more widely separated but not sparse; pleura dull, tessellate, punctures rather shallow and obscure, about as close as those of scutellum; basal segment of abdomen somewhat shining, nearly impunctate medially, becoming rather closely but very minutely punctate laterally, punctures of following segments quite close but exceedingly minute.

MALE�Length 5-6 mm.; black; antennae piceous above, ferruginous beneath; scape fuscous, maculated; tegulae ferruginous, maculated; wings subhyaline, veins and stigma ferruginous; maculations yellow, as follows: labrum, upper portion of mandibles, entire face below antennae, supraclypeal mark triangularly pointed above, lateral face marks extending above antennae, very broadly truncate and not divergent from eyes, narrow stripe on outer surface of scape, tubercles, anterior spot on tegulae, two conspicuous maculae on collar, lower surface of front femora, front tibiae in large part, base and apex of mid tibae, these connected by a narrow line on outer surface, basal half of hind tibiae, all spurs and tarsi, but more apical tarsal segments reddened; posterior face of front tibiae ferruginous, legs otherwise piceous; face narrowed below; cheeks and eyes subequal in width in lateral view; scape slender, rather strongly flexed; 1st and 2nd segments of flagellum somewhat broader than long, succeeding segments as long as or longer than broad; front coxae simple; dorsal face of propodeum sloping, no longer than metanotum, posterior face more finely reticulated, not at all carinate laterally, lateral faces somewhat shining and obscurely punctate; punctures of scutum fine, deep and distinct, close but not crowded, those on scutellum and pleura slightly more coarse and sparse; abdomen rather dull, basal segment minutely and quite closely punctured, following segments more tessellate than punctate.

DISTRIBUTION--- Generally distributed through the Eastern United States and Canada from the New England states west to Minnesota and southward to Mississippi and Georgia; April to October.
FLOWER RECORDS�This species visits a wide range of f-lowers, with records in the following genera: 4pocyni�in, Ceanothus, Cephalanthus, Crataegus, Houstonia. Hypericum, Pycnanthemum, Pyracantha, Rhus, Rubus, Salvia, Solidago and Zizia. The following additional genera are listed by Robertson (1929) : Amorpha, Aruncus. Asclepias, Blephilia, Boltonia. Campanula. Cicuta, Clematis. Comas. Cryptotaenia. Erigeron, Eryngium, Eulophus, Eupatorium, Euphorbia, Fragaria, Geranium, Geum. Gnaphalium, Heracleum, Hydrangea, Krigia. Lactuca, Lepidium, Lycopus, Malva. Nelumbo, Osmorrhiza, Oxypolis, Pastinaca, Petalostemon, Philadelphus, Polygonum, Polytaenia, Potentilla, Ptelea, Salix, Sanicula, Sium, Stellaria, Stenanthiem, Symphoricarpus, Taenidia, Thaspium, Valerianella, Veronica and Viburnum.
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