136 KANSAS UNIVERSITY SCIENCE BULLETIN. 



and fused one upon the other that practically only the region ot 

 each could be indicated roughly in figure 1. The origin of the 

 anterior wing may be seen in figure 1, bp. Just cephalad of 

 its base are two fleshy processes — the cephalic, larger and some- 

 what renifoi*m in shape; the articulatory epidemes, artep. 

 Cross sections show the larger epideme to be almost spherical, 

 with a broad, short base or pettiole. 



The mesosternum is rectangular, wider than long, anterior 

 margin somewhat convex, with corners rounded. The coxal 

 cavities or acetabula are large, ovate, and are situated on the 

 posterior margin (35-11). 



When the mesothorax is dissected free from the other seg- 

 ments, and viewed from behind, the endoskeleton is plainly 

 seen. I shall not attempt to give the orientation and detailed 

 description of its different parts, which may be seen in 27-2 

 (partly diagrammatic). This internal skeleton is a complex 

 of plates and rods, braced in all directions, and fused with the 

 outer sclerites of the segment. Three different internal pro- 

 jections may be seen, dorsal, lateral, and ventral. The dorsal 

 piece, the phragma, phrg, is a symmetrical, transverse plate 

 projecting ventrad. A similar structure in the mesothorax of 

 a stag beetle is figured by Packard (Textbook of Entomology) 

 and called "Diaphragm for the attachment of the tergal mus- 

 cles of the metasternum." On each side there is a simple pro- 

 jection which seems to correspond to the apodeme, apod. The 

 lower projection or apophyse ("medifurca," according to Pack- 

 ard) is seen at apoph, and in 55-11, and is shaped like a 

 letter "Y" ; its dorsal edge is hollowed out, this hollow together 

 with a similar one on the lower edge of the phragma above 

 giving passage to the digestive system, etc. (;?7-33, c.) 



The mesothorax is built for great strength, the sclerites be- 

 ing much fused and the internal structures all large and heavy. 

 Although this segment carries the anterior wings, which are 

 used mainly in flight, I have no evidence that this insect is a 

 very strong flyer ; on one occasion a specimen was captured on 

 the top of a high building, but probably it was carried to such 

 a height independent of its own flying powers, by a strong wind 

 blowing at the time. 



Metathorax. — This segment is the strongest in structure of 

 the thoracic segments, and the endoskeleton and external scle- 

 rites are so strongly fused that the homologies of this region 

 present a great many perplexing problems. I shall proceed to 



