l8o UNIVERSITY OF COLORADO STUDIES 



Colorado have been included in the tables, largely for purposes of com- 

 parison. These nearly all live in New Mexico, and consequently may 

 be considered to belong to the Rocky Mountain fauna. 



Numerous fossil bees are known from the Miocene shales of Florissant. 

 These are not included in the keys, but it will be useful to present a list. 

 Those marked with an asterisk belong to extinct genera: 



Halictus miocenicus Ckll. *Protomelecta brevipennis Ckll. 



Halictus florissantellus Ckll. Anthophora melfordi Ckll. 



Halictus scudderiellus Ckll. Megachile prcedicta Ckll. 



*Libellidapis antiquorum Ckll. Anthidium scudderi Ckll. 



*Lithandrena saxorum Ckll. Anthidium exhumatum Ckll. 



*Pelandrena reducta Ckll. Dianthidium tertiarium Ckll. 



Andrena sepulta Ckll. Heriades laminarum Ckll. 



Andrena clavula Ckll. Heriades halictinus Ckll. 



Andrena hypolitha Ckll. Heriades bowditchi Ckll. 



Melitta willardi Ckll. Ceratina disrupta Ckll. 



*Cyrtapis anomalus Ckll. *Calyptapis florissantensis Ckll. 



Descriptive Terms 



Head (See Fig. 2) 



Vertex: top of head. 



Occiput: region behind the vertex. 



Cheeks: region behind the eyes. 



Front: region between the vertex and the antennae. 



Face: region below the antennae, chiefly occupied by a large central plate, the clypeus. 



Ocelli: the three simple eyes on upper part of head. 



Malar space: the space between eyes and mandibles. 



Antennae: 12-jointed in males, 13-jointed in females; the long basal joint is the 

 scape, the apical part, of many joints, the flagellum. 



Facial foveae: depressed areas on each side of face parallel with the eyes. 



Labrum: the plate below the clypeus, more or less covered by the mandibles. 



The mouth parts are sufficiently explained in the figure. The blade of maxilla (that 

 part of maxilla beyond the palpi) is often called the galea, but it is probably equivalent 

 to the galea and lacinia fused (cf. Trans. Amer. Ent. Soc, Vol. XXIX, p. 185). The 

 tongue is often called the glossa. 



Thorax 



When the thorax is seen from above, the prothorax appears in front, behind the 

 head; it has lateral lobes, approaching the tegulae, known as the tubercles. The large piece 

 following the prothorax is the mesothorax or mesonotum, there may frequently be seen 

 upon it two grooves, the parapsidal grooves. The next piece, just behind the level of 

 the wings, is the scutellum; the axillae are small plates on each side of it, sometimes pro- 

 duced into spines, which are often described as the lateral spines of the scutellum. The 

 postscutellum, a short sclerite, follows the scutellum, and behind this is the metathorax 



