THE BIoLoGy OF THE CHRYSOPIDAE 1311 
which inserted its jaws through the epidermis of a leaf and reached a 
leaf miner. Walsh and Riley (1868) wrote of a larva which attacked a 
eurculionid larva in a peach. More common are their attacks on small 
caterpillars, mites, and young or small spiders. Caterpillars larger 
than chrysopid larvae can ward off the attacks of the larvae by turning 
the head around or twitching suddenly as soon as touched. Mealy bugs 
and mites are readily eaten. Small spiders, especially recently hatched 
ones, are excellent food for young larvae. Marlatt (1895) wrote of 
attacks of the larvae on the pear psylla. Both adults and nymphs of 
Psyllidae are readily eaten. Experiments were conducted chiefly with 
the psyllid species on English ash. A larva of Chrysopa chi fed for 
some time on a much weakened dolichopodid fly. 
Chrysopid larvae are not omnivorous. Not all heavily chitinized 
insects can be pierced by the Jaws; and very active insects can be caught 
only with difficulty. Active larvae, as, for example, fly maggots, 
frighten away the chrysopid larvae. Cocecinellid, chrysomelid, and 
syrphid larvae, all of which occur in association with chrysopid larvae, 
are not commonly used for food except perhaps when just hatched. 
In the way of artificial foods, beef tea and a weak sugar solution were 
used. <A cotton plug or a piece of absorbent cotton was dipped into the 
liquid, and the larvae came to the cotton and sucked up the drops. They 
fed on both these liquids, but whether they could be reared on them was 
not determined. Both cane-sugar and maple-sugar solutions served 
successfully for food. The larvae sucked up drops of water also when 
it was provided. 
Larval feeding 
The rapidity of feeding, as well as the search for aphids, is some- 
what dependent upon how hungry the larva is. When it is very hungry 
but not weakened, its movements are very agitated and it may even walk 
over a few aphids without observing them. 
After the larva has impaled an aphid, feeding proceeds as follows: 
The chief movements, as seen from the dorsal side, are the sliding back 
and forth of the maxillae in the grooves of the mandibles. This is a 
regular forward-and-backward movement. If both jaws are inserted in 
the aphid, the two maxillae move together, pulling the labral region 
backward and forward with it. The aphid is readily turned over and 
over by spearing it on one jaw, then turning it with the other, and so on, 
quickly seesawing it back and forth until it is thoroughly exhausted. At 
the end of the feeding process, the aphid is turned over and over, 
squeezed out, and finally speared on one jaw. This jaw is moved far 
outward and the aphid is pushed off the jaw by the tip of the other jaw. 
