Extracted from THE POLLEN-COLLECTING BEES OF THE ANTHIDIINI OF CALIFORNIA (Hymenoptera: Megachilidae) by Grigarick A., A. (1968).
This species was previously divided into four sub¬species on the basis of extent of yellow coloration. These yellow markings exhibit the north-to-south clinal pattern typical of several other species. D. sub¬parvum subparvum and gallatinae show the least color while swenki of southern California is the most highly maculated. The black areas may be some¬what brownish, as is the case with the type of galla-tinae. Specimens having white maculations have been observed from British Columbia and Nevada and with the addition of future collections, these speci¬mens may warrant a subspecific name. Tergum VII (fig. 156) of the male of subparvum shows similari¬ties to that of parvum (fig. 153) but is distinguished from it by having a wider median lobe and a blunt appearing penis valve (fig. 158). The female of sub-parvum is separated from parvum only by subtle differences of the sternum VI. This sternum is generally larger, more rounded apically than parvum (figs. 188, 189) and the surface of subparvum appears slightly depressed if the pollen is cleared from the scopa.
D. subparvum is fairly common in the mountains of eastern and southern California, but in the Coast Range it is limited to the extreme southern end. Specimens observed from California total 94 males and 88 females.
CALIFOflNIA INSECT SUflVEY UHlVtJtllTT Of CALIFORNIA
Biological information on this species is limited to the recording of visitations on members of several diverse plant families. The majority of these were found on the Compositae.