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 considerably 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. 
2 
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, pl. 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, 1901a; 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 almost straight tube inclosed by the coiled, 
perforated sheets of adipose tissue. The esophagus is slender, opening 
into the hypopharynx. The proventriculus 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 are four small, pocket-like gastric caeca near the posterior end 
of the ventriculus, which are not mentioned as occurring in Holorusia. 
At the juncture of the ventriculus and the small intestine are the four 
