LIMNOPHILIDE. 
their tough stone cases to the edges of rocks in swift water, without 
search for protecting crevices. 
In this family, with the exception of the genus Neophylax, we 
have noted no attempt at gregarious grouping, except when acci- 
dent brings the larve together. In Neophylax there is an unmis- 
takable gregarious instinct developed when the prepupal period 
approaches. At this time larve gather in compact masses on cer- 
tain parts of certain stones, while other similar stones in the same 
part of the stream remain uninhabited. 
Foop oF Larva:.—It seems probable that the larve are al- 
together herbivorous when living under natural conditions, but’ in 
the confines of aquaria they will often become carnivorous, or even 
cannibalistic. 
The vegetation eaten by most. species consists of vascular 
plants, living or dead, with more consideration for the convenience 
of the larve than for the condition of the food. 
A few species, such as Limnophilus submonilifer, rasp the soft 
outer portions from submerged sticks and stems, and thus procure 
a diet that is often a mixture of higher plant tissue and diatoms— 
sometimes it is almost altogether diatomaceous ooze. 
Periop oF EMERGING.—From the time when Platyphylax be- 
gins to emerge, while the first warm spring sun still shines on the 
snow of late winter, until Neophylax and a few others cease their 
flight in the snow of early winter, there is no period without some 
species of Limnophilid. 
Though on the wing from the snows of spring till the snows 
of fall, the adults are found in maximum numbers of species dur- 
ing late spring or early summer. In June, for a short time only, 
the greatest number of species are in flight, but there are other 
species for every period of the summer, and a few, such as Limno- 
philus submonilifer, continue to emerge during the greater part of 
the summer. Such species do not have a definite season when all 
the individuals occur as larvee, pupz, or adults, but can be found 
in all stages during most of the summer. 
Description oF Larvai.—tIn form the larve are cylindrical. 
The head fits well into the first thoracic segment and is carried 
pointing downward at a decided angle to the rest of the body. The 
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