17 
forms, such as some Agrionide, most of the Aschnide, Libel- 
lula, Sympetrum, and Mesothemis scatter widely inland. Sym- 
petrum will be seen about fields and lawns, and the schnide 
in the vicinity of houses. 
FOOD RELATIONS, 
The nymphs are all predatory in habit. Most species 
remain in ambush, aided by coverings of sand, mud, silt, and 
algal growths, and by their own protective coloring, until their 
prey wanders within reach. Anar junius and a few others 
choose their prey. All capture it with a marvellously sudden 
extension of the labium, bringing it into the grasp of the for- 
midable lateral labial lobes. Almost all kinds of small aquatic 
animals appear on the bill of fare of the group as a whole. 
The Agrionidw have a seeming preference for Hntomostraca 
and May-fly nymphs. The vegetation-inhabiting species have 
the most varied diet, including especially back-swimmers 
(Notonecta) and water-boatmen (Corisa), small crustaceans, such 
as Asellus and Allorchestes, thin-shelled mollusks, like Physa, 
coleopterous and dipterous larvee, and even the younger or 
weaker members of their own order. Anax takes even the 
thicker-shelled univalves. like Amnicola. The deep-water Ep/- 
cordulia feeds principally on small mollusks, such as Amnicola 
and Physa, as well as on other life of the bottom. The A’sch- 
nide, especially Anar, are most omnivorous creatures. The 
larger odonate nymphs eat very young fish, and in some cases 
appear to have caused a sweeping destruction of large numbers 
of them. 
On the other hand, the nymphs are apparently eaten prin- 
cipally by fishes and by one another; hence their need for hid 
ing places in mud and sand or among matted vegetation. 
the course of Professor Forbes’s studies of the food of 
(88a, pp. 485, 524) he found odonate nymphs most ?' 
(twenty-five per cent.) in the food of the grass pic. 
vermiculatus), and forming ten to thirteen per cent 
of the crappie (Pomowis annularis), the pirate ner 
