THE BIOLOGY OF THE CHRYSOPIDAE 1329 
largely used for this purpose. Aphid skins and dead aphids call forth 
responses similar to those called by live aphids. When the live aphids 
are encountered, their movements are readily detected, and then they 
are quickly seized and devoured. 
Flight 
The flight of the adult is slow, heavy, and rather awkward. The 
wings are large and the body is comparatively heavy. In the sun, the 
light is reflected by the wings but the usual color impression is green. 
Although the flight of the chrysopids is distinctive, they are frequently 
confused with some Plecoptera (especially Chloroperla), Mecoptera, 
Hemerobiidae, and the smaller Lepidoptera. 
Activity of adults 
The inactivity of the adults during the day has been commented 
on by many writers from Réaumur to the present time. The insects 
prefer to remain quiet on trees, shrubs, and herbs, during the day, and 
fly chiefly in the morning and evening. They sit probably most often 
on the under side of the leaves. Sweeping and beating are the most 
successful means of taking them during the day. 
At Ithaca and at Milwaukee the greatest activity was manifested in the 
evening, aS was evidenced by the attraction of the adults to the electric 
lights, especially are lights. It was found that a better collection could 
be taken here in a few hours on a favorable evening than in several days 
of sweeping. The activity of the adults begins early in the evening, 
perhaps at seven o’clock in summer, and their numbers increase until 
about nine or ten o’clock. The greatest numbers of adults on the wing 
have been observed on warm, still summer evenings. If a rain be near- 
ing, the conditions are still more favorable. In Virginia, though 
frequent watches were made at lights, comparatively small catches 
resulted and nothing rare was ever taken. Adults are somewhat 
attracted also to sugar put out for moths at night. 
Cleaning the antennae and pulvilli 
An interesting performance seen frequently in adult chrysopids is 
the cleaning of the pulvilli and the antennae. The right antenna is 
cleaned by the right front leg. The tarsus is looped over and the antenna 
is drawn through the loop. The long hairs on the tarsal segments serve 
to remove attached debris. The left antenna is cleaned by the left 
tarsus In the same way. 
