~ 
TRICHOPTERA. — PHRYGANEID. 65 
more elongated ; and in the latter of these genera M. Pictet repre- 
sents the external lobe as articulated and palpiform. My jig. 68. 16. 
represents the maxilla of the larva of Phryganea pellucida, after De 
Geer. The head exhibits no trace of antennae; the corneous cover- 
ing of the eyes is very small, and apparently composed of points at 
the sides of the head, and destitute of reticulations; the three tho- 
racic segments of the body are leathery, each being furnished with a 
pair of legs, the anterior pair of which are shorter and stronger than 
the others. In the larve of the true Phryganee there is a slender 
horn between the anterior legs, which Reaumur considered to be the 
spinneret, but the use of which has not been ascertained ( fig. 68. 17. 
prosternum of larva of P. striata Pictet). The nine abdominal seg- 
ments are more fleshy, being seldom exposed beyond the mouth of the 
case, in which they retain their station by means of three conical 
fleshy tubercles on the first segment, and by the two moveable articu- 
lated appendages, of variable form, at the extremity of the body. In 
those species observed by M. Pictet, which reside in fixed cases, 
these abdominal tubercles are wanting, and the anal hocks are elon- 
gated, and placed upon long footstalks ( fig. 68. 18.), giving them great 
capacity for movement, and enabling them to fix themselves firmly 
in their rough and irregular retreats. Other peculiarities exist in the 
form of this organ in the different genera, which correspond with their 
various modes of life and movements. ‘The abdominal segments are 
moreover furnished with white membranous filaments, of various 
forms, which are the external organs of respiration. 
The food of the larva has been stated to consist of minute aquatic 
larvee, and such is the case with Hydropsyche, M. Pictet having ob- 
served that the larvee prey upon those of other aquatic Neuroptera, and 
even upon each other, in a state of captivity ; but the greater number 
are purely herbivorous, the structure of their jaws being fitted for 
gnawing vegetable matters; and M. Pictet supplied them with willow 
leaves, upon which they fed well; the larger species devouring the 
whole leaf, but the smaller ones leaving the veins entire ; they would, 
however, occasionally attack other aquatic larvee. 
From the common occurrence of these caddice worms, it is not sur- 
prising that they should have attracted the attention of the early na- 
turalists, by some of whom they were known under the names of 
Ligniperdez ; and Reaumur and De Geer have entered very fully into 
their natural history and structure. The former of these authors 
VOL. Il. x 
