758 Charles Paul Alexander 



abdominal spiracles are protuberant, notably the pair on the second 

 segment. 



The genitalia. — The genital sheaths conceal the adult organs within. 

 In the male the valves are usually subequal or the sternal valves are 

 a little the longer. In the female the sheaths, or acidothecae, of the 

 ovipositor usually have the dorsal valves considera]:)ly longer than the 

 sternal valves and distinctly upturned at their tips. In the few groups 

 with fleshy ovipositors, the female cauda is very difficult to distinguish 

 from the cauda of the male. The valves are variously armed with spines 

 or lobes, at or before the tips. 



internal morphology 

 The internal morphology and anatomy of the crane-fly larva are here 

 considered in general terms only. The two genera that have been studied 

 in greatest detail by the writer are Eriocera and Antocha. The most 

 important literature on the various systems of the body is cited in order 

 to make reference to it more easily available. 



The digestive system 

 The most important literature on the digestive system is as follows : 



Ptychoptera. Grobben, 1876; Van Gehuchten, 1890. 



Chionea. Brauer, Egger, and Frauenfeld, 1854:613-614, pi. 11, fig. 4. 



Dicranota. Miall, 1893:242-245. 



Phalacrocera. Miall and Shelford, 1897:347-351; Bengtsson, 1897. 



Ctenophora. Anthon, 1908:546-551, figs. 12-35. 



Holorusia. Kellogg, 1901 a; Comstock and Kellogg, 1904:56-57. 



Herbivorous larvae (Tipula, Holorusia, Ctenophora, Phalacrocera) 



In the larva of herbivorous species the alimentary canal extends the 

 length of the body as an ahuost straight tube inclosed by the coiled, 

 perforated sheets of adipose tissue. The esophagus is slender, opening 

 into the hypopharynx. The proven triculus has a large esophageal invagi- 

 nation at its anterior end. The ventriculus has at its anterior end four 

 elongated ventricular caeca, these being of two distinct lengths in pairs 

 (didynamous) in Ctenophora, and all four alike in Holorusia. In Cteno- 

 phora there arc four small, pocket-like gastric caeca near the posterior end 

 of the ventriculus, which are not mentioned as occurring in Holorusia. 

 At the junctui'e of the ventriculus and the small intestine are the four 



