128 KANSAS UNIVERSITY SCIENCE BULLETIN. 



female of twelve. They are conveniently divided into three 

 parts: the scape (s), the largest and stoutest of the joints, 

 which is differentiated into a small bulbous basal portion (b), 

 fitting snugly into the socket, and the main limb, which is quite 

 densely hairy ; the pedicel (p) , a short joint springing from the 

 scape ; and lastly, the flagellum or filament F, constituting the 

 remaining many-jointed and commonly uniform portion. 



Mouth Parts. 

 (PI. XXIII, figs. 7-10.) 



The large oral cavity bears the complicated type of mouth 

 parts found in most Hymenoptera. If we consider the clypeus 

 to be the dorsal (upper) edge of the oral cavity, we have depend- 

 ing therefrom, though but little exserted, the labrum. This is 

 indistinctly bilobed, and bears some short, stout bristles. From 

 the ventral (opposite or lower) side of the oral cavity hang 

 the cardines of the maxillse (fig. 7, C), contributing to and sup- 

 porting the latter, which may in turn partly enclose and pro- 

 tect the median composite labium, or lower lip. The latter, 

 unlike the maxillse, is not directly secured to the head skeleton, 

 but is separated from it by an intervening membrane. 



Epipharijnx. (PI. XXIII, figs. 8 and 10, EPH.) The epi- 

 pharynx is a slightly bilobed and pilose membrane which 

 hangs down from the base of the labrum. Laterally it is pro- 

 tected by a thin, weakly chitinized plate, which extends for 

 a short distance into the mouth opening. The epipharynx may 

 be termed the roof of the mouth. At the pharyngeal entrance 

 is the pharyngeal plate, which is opposite the epipharynx. It 

 is a transverse chitinized piece, extending from each side an- 

 teriorly as a pair of broader subparallel portions, and poste- 

 riorly as a narrow pair (fig. 10, r), which converges to the 

 oesophagus. These (r) are termed by Sharp the epipharyngeal 

 sclerites. The piece s, figures 8 and 10, is stouter than r, and 

 extend from the dorsal (under) side of the mentum (Af) up to 

 the anterior of the pharyngeal processes. The pair s is termed 

 by Sharp the hypopharyngeal sclerites, and would seem largely 

 to support the oral tissue, and in a great measure keep the 

 mouth cavity open when necessity demands. 



The mouth parts thus far described do not differ very ma- 

 terially from those of the bumblebee as given by Sharp (Camb. 

 Nat. Hist. Ins., II, 14; 1901). 



