NORTH AMERICAN CADDIS-FLY LARVE. 
DESCRIPTION OF THE LArva.—Length, 30—35 mm.; breadth, 
5 mm. The head and thorax are considerably broader and flatter 
than those of P. vestita. 
Head.—The ground color is light straw-yellow. A dark-brown 
mark begins at the front margin of the head behind each mandible 
and extends obliquely back, paralleling the side of the frons, to 
the hind margin of the head, where it almost touches the mid-dorsal 
line. A dark-brown mark begins a short distance behind and be- 
low each eye and extends back to the hind margin of the head. The 
eyes are narrowly bordered with white. The frons is traversed 
from the front to the hind margins by a dark-brown median mark 
with irregular margins (figure 36). 
The mandibles are dark-brown and black, except a somewhat 
triangular mark on the outer margin, which is paler; other parts of 
the head are straw color. 
The Thorax.—Straw-yellow, marked on its upper surface 
with brown, as shown in figure 24. The pronotum is margined in 
front by a narrow line of very dark brown; behind this line there 
is a brown mark, on its hind margin there are similar but narrower 
markings of brown which, in the normal position of the larve, are 
covered by the metathorax. 
The meso- and meta-thorax are light-green in life, with fine 
colorless markings, which are subject to considerable variation in 
pattern. 
The supra-coxal plates are dark-brown, margined with black. 
The legs are straw-yellow with narrow black marks on the 
outer edges of the bases of the cox, and shadings of light-brown 
on the margins. The outer surfaces of the coxe of the first and 
second pairs of legs are thickly set with minute thorns, plainly 
visible only in prepared mounts, but much larger than those of 
P. vestita, in which species the thorns are visible only with the 
compound microscope. 
DESCRIPTION OF THE Pupa:.—Only cast pupal skins are in our 
collection. Vorhies states: “Length, 25—28 mm.; width, 6 mm. 
Antennz extending to the sixth segment. Body in life, green; a 
fuscous band extending along the dorsal wall of the abdomen on 
either side.” 
Our cast skins show the following characters: The mandibles 
(figure 37) are almost twice as long as the labrum. ‘The lateral 
34 
