88 • KANSAS UNIVERSITY SCIENCE BULLETIN. 



there being found upon dissection an interior spine nearly as 

 long as the two basal segments. 



In caudal aspect the head presents a concave surface, smooth 

 and unhaired or punctured. Only small margins of the com- 

 pound eyes can be seen. (Fig. 40, pi. XII.) 



Branching out from the occipital plates w^hich surround 

 the cavity are seen the tentoria {t, fig. 40, pi. XII) ; from these 

 is a narrow chitinized bar with three pairs of branches — one 

 pair inward to support the oesophagus and attached to the 

 cephalic face, just above the suture for clypeus, the second 

 pair toward the thorax to help join the head to the thorax, and 

 the third pair join to meet the bar which supports the labium. 



Mouth Parts. 



In ventral aspect (fig. 37a, pi. XI) the clypeus appears as 

 a fleshy, swollen cushion, very large in proportion to the other 

 sclerites, and rising in a dome. It is haired and its lateral 

 edges fit down tightly upon the other sclerites. (See fig. 37a 

 at y, pi. XL) 



Labrum. Lying against the distal edge of the clypeus is the 

 labrum, light in color, and also fleshy and slightly elevated, but 

 smooth and unhaired. It is elongated, with lateral edges curv- 

 ing inward distad. (See lb, fig. 37a, pi. XL) In its under 

 side the edges are seen to curve inward to support the epi- 

 pharynx. The distal edge is pilose. 



Epipharynx. Arising beneath and extending beyond the 

 labrum is the external portion of the epipharynx. It is pointed, 

 and grooved on its inner surface, fitting closely over the open- 

 ing in the first segment of the beak, and making, with the 

 labium, an almost perfect tube (fig. 38b, pi. XII) for the setae, 

 which come together and enter the beak at this point. It ex- 

 tends exteriorly to the joint between the first and second seg- 

 ments. (Fig. 37a, pi. XL) On its inner or under side the 

 epipharynx is grooved and extends in a slender, thin plate to 

 the hypopharynx, which will be discussed later. (Fig. 39, 

 pi. XII.) 



Mandibular Sclerites. (Fig. 37a at m, pi. XL) Lying 

 laterad of the clypeus is a slender, curved plate immovably 

 sutured with the clypeus. Muir and Kershaw seem to con- 

 sider this sclerite as a lateral projection of the clypeus. 

 They figure a mandibular suture but no scelerite. I find 

 this suture between the clypeus and the projected plate of 



