Microsphecodes Eickwort & Stage, 1972

Engel, Michael S., 2013, A new species of Microsphecodes from Peru, with notes on the classification of the genus (Hymenoptera: Halictidae), Journal of Melittology 2013 (24), pp. 1-9 : 2-3

Genus Microsphecodes Eickwort & Stage

DIAGNOSIS: Small, cleptoparasitic halictine bees with generally fine punctation and sparse setation; head, mesosoma, legs, and metasoma usually with extensive areas of yellow, orange, testaceous, or ferruginous coloration. Head broad; clypeus 2.8– 4.5 times wider than long, sometimes with faint longitudinal depression. Mandible simple (i.e., without subapical teeth). Labrum with transverse basal elevation, distal process broadly rounded. Hypostomal bridge sclerotized anterior to anterior angles of hypostomal carinae. Compound eyes generally bare or with sparse, scarcely visible setae, rarely with more elongate setae (more elongate setae are presently known only in M. trichommus ). Preoccipital area rounded or weakly carinate. Pronotum with horizontal surface poorly defined and narrow medially, rounded medially onto anterior surface; lateral angle angulate, anterior ridge prior to angle carinate or rounded, dorsal ridge rounded, lateral ridge scarcely developed, typically rounded or faintly carinate bordering dorsolateral angle. Anterior border of mesoscutum gently convex, no strongly convex or vertical surface. Mesoscutum and mesoscutellum polished, finely punctate; mesoscutellum not biconvex; propodeum irregularly reticulate-rugose posteriorly; basal area of propodeum slightly shorter to slightly longer than mesoscutellum, semilunar. Legs slender. Forewing with pterostigma enlarged, convex; marginal cell long, apex acute, free part of marginal cell nearly three times as long as part bordering submarginal cells; submarginal cells do not or scarcely extend beyond apex of pterostigma; second and third submarginal cells, when present, each receiving a rs-m crossvein ( M. xaymacensis Engel has only two submarginal cells). Metasoma polished; first metasomal tergum longer than broad, with no or scarcely any constriction between first and second terga.

♀: Female without scopa; metabasitibial plate completely absent; metatibia without spine-like setae or pegs; inner metatibial spur simple. Pygidial plate narrow, apically rounded, parallel-sided or nearly so, marginal carina scarcely extending onto tergal disc.

♂: Male antenna short, resembling that of female. Metabasitarsus not fused to second metatarsomere. Pygidial plate well defined, broadly or narrowly rounded or subtruncate. Sterna IV – VI with graduli absent or defined only basally, not extending over half distance to margin. Gonobase large; gonocoxae without striations; convex, seta-bearing, ventral gonostylar process short relative to Sphecodes , surpassed by expanded dorsal gonostylar process; penis valve slender, with sharp dorsal crest, without ventral prong .

COMMENTS: Microsphecodes is most similar to Nesosphecodes , both sharing a fine punctation on the head and mesosoma (coarse and closely packed punctation in Sphecodes ), shortened submarginal cells, very broad clypeus (even more so in Nesosphecodes ), absence of vertical pronotal lateral ridge or carina, and absence of a defined mesoscutal anterior vertical surface. The genus differs from Nesosphecodes by the extensive yellow, orange, or testaceous areas of integument (entirely black in Nesosphecodes ), the less broad clypeus (broader in Nesosphecodes : vide metrics in Engel , 2006a), shorter mandibles (mandibles longer than the compound eyes in Nesosphecodes , at most about as long as compound eye in M. xaymacensis ), the longer subantennal sulci (length only about as long as antennal torular diameter in Nesosphecodes ), and larger body size (7.8–9.2 mm in length among species of Nesosphecodes vs. 3.5–6 mm in Microsphecodes ).