Nerve-winged Insects; Scorpion-flies; Caddis-flies 235 
Mantispa Iarvas find them out, tear a hole in the bag, and enter among the 
eggs; here they wait until the eggs have attained a fitting stage of develop¬ 
ment before they commence to feed. Brauer found that they ate the spiders 
when these were quite young, and then changed their skin for the second 
time, the first moult having taken place when they were hatched from the 
egg. At this second moult the larva undergoes a considerable change of 
form; it becomes unfit for locomotion, and the head loses the compara¬ 
tively large size and high development it previously possessed. The 
Mantispa larva—only one of which flourishes in one egg-bag of a spider— 
undergoes this change in the midst of a mass of dead young spiders it has 
gathered together in a peculiar manner. It undergoes no further change 
of skin, and is full-fed in a few days; after which it spins a cocoon in the 
interior of the egg-bag of the spider, and changes to a nymph inside its larva- 
skin. Finally the nymph breaks through the barriers—larva-skin, cocoon, 
and egg-bag of the spider—by which it is enclosed, and after creeping about 
for a little appears in its final form as a perfect Mantispa.” 
Thus in this insect the larval life consists of two different stages, one 
of which is specially adapted for obtaining access to the creature it is to 
prey on. 
The Coniopterygidae include a few tiny, obscure insects, the smallest 
members of the order. They have wings with very few cross-veins, and 
both wings and body are covered with a fine whitish powder, hence the name 
“dusty wings” which entomologists apply to them. Only two species are 
known in this country, of neither of which is the life-history known. In 
Europe the larvae of a “dusty wing” species have been found feeding on 
scale-insects. When full-fed these larvae spin a silken cocoon, within which 
they transform. 
The small and little-known order Mecoptera includes certain strange 
little wingless, shining black, leaping insects found on snow, some larger 
net-veined-winged insects with the abdomen of the males ending in a swollen 
curved tip bearing a projecting clasping-organ resembling slightly a scor¬ 
pion’s sting in miniature, and a number of still larger, slender-bodied, narrow¬ 
winged insects. The only popular name possessed by any of these insects 
'is that of scorpion-flies, which has been given the few species with pseudo¬ 
stings. For these scorpion-flies are not stinging-insects, although the males 
can pinch hard with the caudal clasping-organ. But little is known of the 
life-history of any members of the order, nor is much known of the habits 
of the imagoes. 
There are but five genera in the order, which may be distinguished by 
the following key: 
