ROCKY MOUNTAIN BEES l8l 



propodeum or median segment. Morphologically this is considered to be part of the 

 abdomen, but even so, the name metathorax is appropriate. The basal area of the meta- 

 thorax is just behind the postscutellum. The large sclerites at the sides of the thorax con- 

 stitute the pleura. At the base of the anterior wings are round scalelike bodies, the tegulae. 



Wings 



The venation of the wings is explained in Fig. i. 



Legs (See Fig. 3) 



The basal part of the leg consists of two short segments, the coxa and trochanter, fol- 

 lowed by the long and robust femur, after which comes the tibia, with one or more apical 

 spurs. The remaining joints constitute the tarsus; of these the first is longer than the others 

 and is called the basitarsus or metatarsus, the latter term being morphologically incorrect. 

 The last tarsal joint bears the claws, between which may be a small pad, the pulvillus. 

 The scopa is the pollen-collecting apparatus, consisting of modified hairs on the hind legs. 



Abdomen 

 Six dorsal segments are visible in the female, seven in the male. The ventral scopa 

 is the brush of hairs covering the under surface in certain females. 



Sculpture 

 The tegument or chitinous surface is variously sculptured; punctate, striate, rugose, 

 etc. The terms are self-explanatory, except punctate or punctured, which refers to small 

 depressions looking like punctures of the surface, but not actual perforations. 



Synopsis of Classification 

 solitary bees 



A. Tongue short, broad, obtuse, emarginate at apex. COLLETIFORMES. 



1 Hairy bees; anterior wings with three submarginal cells, COLLETIDAE 



Colletes Latr. (P.) 



2 Black bees with little hair, nearly always very small, face in nearly all the 

 species with yellow or white markings; only two submarginal cells, PRO- 

 SOPIDIDAE. Prosopis Fabr. (P.) 



B. Tongue more or less elongate, pointed, not emarginate; no ventral abdominal scopa. 

 A NDRENIFORMES 



1 Tongue more or less short, dagger-like; marginal cell pointed; usually three 

 submarginal cells; maxillary palpi 6-jointed, ANDRENIDAE. 



a Females with facial foveae; basal nervure nearly straight; hind 

 trochanters of females with curved tuft of hair. Andreninae. 

 Three submarginal cells; mostly black species. 



Andrena Fabr. (P.) 

 Two submarginal cells. 



Non-metallic species. Parandrena Rob. (P. D.)- 



Metallic green or blue species. 



Diandrena Ckll. (P. D.) 

 b Andrena-like bees, with three submarginal cells, the second small; 

 tegulae usually large; hind legs in male usually modified; abdomen 

 often with opalescent green or blue bands. Nomiinae. 



Nomia Latr. 1 (P.) 



1 The allied genus Dieunomia occurs on the plains. D. marginipennis, Cresson, occurs at Rockyford 

 (Gillette) and D. xerophila Ckll. at Sterling (Johnson). These are large bees, with the male antennae modified 



