Lasioglossum petrellum (Cockerell, 1903)

Gardner, Joel & Gibbs, Jason, 2020, The ‘ red-tailed’ Lasioglossum (Dialictus) (Hymenoptera: Halictidae) of the western Nearctic, European Journal of Taxonomy 725, pp. 1-242 : 222

The Lasioglossum petrellum species complex

Species included

Lasioglossum droegei , L. griswoldi , L. petrellum , L. tuolumnense , and L. viridipetrellum Gibbs, 2009 [in Gibbs 2009b].

Diagnosis

The Lasioglossum petrellum species complex is an infrequently collected group of morphologically similar species, but each with distinct geographic distributions. It is often easier to identify specimens geographically than morphologically. This group was revised by Gibbs (2009b); users are referred to that work for additional details on the included species.

Females and males of the L. petrellum group can both be recognized by the head very elongate (length/ width ratio 0.88 or more), eyes strongly convergent ventrally, clypeus strongly protruding below the suborbital tangent, and most of the body covered in very fine, dense punctures and strong microsculpture. In addition, females lack an acarinarial fan, and males have the retrorse lobes very small.