236 Nerve-winged Insects; Scorpion-flies; Caddis-flies 
Simple eyes (ocelli) absent. 
Wings well developed; antennae short and thick; body more than J inch long. 
Merope. 
Wings rudimentary; antennae slender; body less than \ inch long. Boreus, 
Simple eyes (ocelli) present. 
Abdomen slender, cylindrical; not ending, in males, in swollen tip with clasping-organ. 
Bittacus. 
Abdomen more robust, and in males conspicuously swollen and curved at tip, and 
bearing pointed clasping-organ. 
Beak elongate, tarsal claws toothed... Panorpa. 
Beak short, triangular; tarsal claws simple... Panorpodes. 
Boreus is the genus of minute leaping black insects which appear occa¬ 
sionally in snow. Four species occur in this country, one, B. calijornicus, 
on the Pacific coast, two in the northern and northeastern states, and one, 
B. unicolor , found, so far, only in Montana. Of the two eastern species, the 
snow-born Boreus, B. nivoriundus , is shining or brownish black, with the 
rudimentary wings tawny; the other, called the midwinter Boreus, B. 
brumalis, is deep black-green. Comstock says that both species are found 
on the snow in New York throughout the entire winter, and that they also 
occur in moss or tree-trunks. The females have a curved ovipositor nearly 
as long as the tiny body. Neither their feeding-habit nor life-history is 
known. 
The genus Panorpa includes the scorpion-flies, of which fifteen species 
are found in the United States. These insects are from J to f inch long, 
with the wings of about the same length. In all, the body is brownish to 
blackish and the wings are clear but weakly colored with yellowish or 
brownish, and have a few darker spots or blotches, which in one or two 
species cover nearly the whole wing-surface. Part of the head projects 
downwards as a short thick beak, the mouth and jaws 
being at the end. The few observations made on the 
feeding-habits seem to show that the scorpion-flies sub¬ 
sist mainly on animal matter found dead. They have 
Fig. 326. Fig. 327. 
Fig. 326.—A scorpion-fly, Panorpa rufescens. (Twice natural size.) 
Fig. 327. —Larva of scorpion-fly, Panorpa sp. (After Felt; three times natural size.) 
been seen to attack living injured and helpless insects. Panorpa rujescens 
