718 CHARLES PauL ALEXANDER 
worms (Patterson, 1908) and other soft-bodied animals. Dissections of 
Tipula abdominalis show the food of this species to consist principally of 
small filamentous algae, diatoms (Diatoma, Navicula, and others), and 
rootlets of small plants. The alimentary tract is often crammed with 
sand or soil particles. The species of Tipula and Nephrotoma that are 
injurious to plants, considered later in this paper under the heading 
Economic Importance, effect their damage by devouring the living tissues 
of the roots. The Cylindrotominae feed on the living tissues of the plants 
on which they dwell; in the case of Phalacrocera, Triogma, and Liogma 
these are mosses, in Cylindrotoma they are the parenchyma and epi- 
dermis of higher plants (spermatophytes). With this habit of feeding 
on plant tissues the extreme of sluggishness of motion is attained. The 
wood-boring species of Tipulinae (such as the species of Tanyptera and 
Ctenophora) feed on the ligneous tissue of the trees in which they occur. 
Other species of crane-flies injure young seedlings by destroying the bark 
and the bast tissues. 
The hexatomine and pediciine forms represent the opposite extreme, 
being for the most part carnivorous or even cannibalistic in their habits. 
In order to capture their prey they are of necessity rapid of movement, 
and in this group the most graceful and active of all tipulid larvae are 
found. The motions of the species are, at times, exceedingly agile and 
snakelike. The food consists of a variety of animal forms. Dicranota 
has been recorded as feeding on worms of the genus Tubifex. Pedicia. 
usually feeds on the larvae of small insects, especially Chironomidae, 
but the large species of this genus and of Eriocera are capable ef capturing 
almost any insect of a size equal to their own. The larvae of Eriocera 
spinosa are able to inflict painful bites on tender parts of the skin of a man. 
Penthoptera, Eriocera, Hexatoma, and most of the limnophiline groups 
likewise feed largely on midge larvae. From one small larva of Limno- 
phila (Dicranophragma) fuscovaria the writer has dissected out the remains 
of two large midge larvae, whose heads were nearly half the size of that of 
the captor. The chitinized mentum in these predacious forms is very 
weak or is lacking, allowing for a tremendous distension of the gular region. 
The mandibles are always developed into powerful curved hooks which 
serve well their purpose of grasping and holding the victims. ‘The 
esophageal region is often retrorsely roughened to prevent the egress of 
anything that has once started down the throat. In addition to the 
