704 CHARLES PauL ALEXANDER 
GENERAL CONSIDERATIONS 
REPRESENTATIVE CRANE-FLY LIFE HISTORIES 
The life histories of but few species of crane-flies have been studied 
in detail. The very nature of the habitat (mud or earth) required by 
most species of the family renders it a most difficult operation to rear 
the species from the egg to the adult and note the various stages, their 
molts, their habits, and other features. The subfamily Cylindrotominae, 
the immature stages of which live on the leaves of various higher plants 
and curiously resemble the caterpillars of certain Lepidoptera, furnishes 
species whose habits are more readily studied than most others, and as 
a result the immature stages of this group are better known, perhaps, 
than those of any other section of the family. Two widely different 
species have been chosen, and their life histories as they are known at 
present are here outlined. The first is a species of Eriocera, a powerful, 
semi-aquatic carnivore; the second is a species of Cylindrotoma, a ter- 
restrial herbivore. In the text which follows, notes on the life activities 
of various other species are given, but the gaps in the knowledge of this 
phase of the subject are very considerable and there still remain innumer- 
able interesting facts to be ascertained. 
Eriocera longicornis (Walk.) 
The common crane-fly Eriocera longicornis is widely distributed over 
the northeastern United States and Canada. Altho the species is local 
in its distribution, the flies may be found in abundance wherever it does 
occur. The situations that favor the presence of these flies are large 
streams or rivers with sand or gravel bottoms and banks. The following 
notes were taken, partly in Fulton County, New York, along the Sacan- 
daga River, and partly in Tompkins County, along Fall and Cascadilla 
Creeks. Some of these data have already been published by Alexander 
and Lloyd (1914:12-18) and by the writer (Alexander, 1915 ¢:149-152). 
On May 27, 1914, the adult flies were exceedingly numerous near the 
village of Northampton, Fulton County. They were present in untold 
myriads, and at every step they arose in clouds from under foot or from 
the leaves of chokecherry on which they rested. They sat on the leaves 
with the head directed away from the observer, ready to take instant 
flight, and at the first approach of a possible enemy they darted up into 
