CALAMOCERATID&. 
Food.—The food of the larve, as demonstrated by examina- 
tions of the contents of many stomachs at different seasons, con- 
sists of fine powder rasped from submerged wood. 
PERIOD OF _E.MERGING.—The specimens in captivity emerged 
from June 4 to July 11. 
DEscRIPTION OF THE Larva.—Length, 18—2o0 mm.; width, 
3 mm. Color of chitinous portions of head and thorax, black 
when viewed with reflected light; when viewed with transmitted 
light, mounted specimens show faintly lighter markings. The 
legs are black, ringed with white. Fleshy portions of prothorax 
and abdomen are pale-brownish white. The anal hooks are brown. 
The Head.—The head is narrowest at its anterior end and 
broadens very gradually to near its base, where it narrows. Behind 
the place of its greatest diameter it is inclosed within the first tho- 
racic segment. The distribution of sete on the dorsal surface is 
shown in figure 149. The frons, figure 160, has a semi-circular 
line of sete, curving away from the cephalic margin and three other 
more widely-separated sete near each side. Like the heavily chiti- _ 
nized portions of the head and thorax, the frons is thickly marked 
by minute transverse lines, from each of which arise several very 
minute hairs, giving, except under high power, a somewhat scale- 
like appearance. The mandibles, figure 154, are deeply grooved 
along their inner margin to the very tip of the apical tooth. Be- 
sides the apical tooth, two lateral teeth are present on each edge 
of the groove. From the groove arise three well-defined brushes 
of hair. The inner brush is directed inward and backward; the 
middle and cephalic brushes are directed inward and toward the 
front; the cephalic brush is the most dense and is composed of 
extremely fine hairs. The labrum, figure 152, is crossed by a row 
GANONEMA AMERICANUS. 
149. Larva. Head and thorax. 156. Larva. Front leg. 
150. Pupa. Mandible. 157. Pupa. Anal appendages, dor- 
151. Case, longitudinal section. sal view. 
152. Larva. Labrum. 158. Larva. Detail of hooklets cov- 
153. Larva. Hind leg. * ering lateral humps. 
154. Larva. Mandible. 159. Larva. Distribution of gills. 
155. Larva. Terminal abdominal 160. Larva. Frons. 
segments. Lateral 161. Pupa. Chitinous plates of left 
view. side of abdomen. 
