6 



out the orchard. On some trees nearly every leaf would have one or two of the 

 eggs of the Chrysopa attached to it. Later nearly full-grown larva; of Chrysopa 

 were found on the pear trees, attacking and devouring the adult Psylla in a 

 very vigorous manner (see tig. 4, d) , and the young larva' were found to feed 

 with great readiness on both the eggs and the young larval Psyllas. It is a safe 

 estimate to say that one lace-wing fly larva will destroy several hundred eggs 

 and larva- of the Psylla, in addition to the adults which it will destroy in its 

 later larval growth. The great abundance of the Chrysopa eggs on the pear 

 trees makes it not at all improbable that the lace-winged fly has much to do with 

 the marked decrease in the later broods of the Psylla. 



The predaceous habits of the lace-wing fly larva' are of common record, and 

 their beneficial character is well known; hut in view of the important role 

 played by this insect in the economy of the Psylla, its life habits may be briefly 

 summarized. The eggs (fig. 4, a), instead of being deposited in rather numer- 

 ously placed clusters or groups, as is 

 the case with some other species, are 

 distributed almost invariably singly on 

 the leaves, rarely two together on the 

 same stalk. The young larva (fig. 5) 

 cuts off the upper end of the egg on 

 emerging, and is surprisingly large in 

 comparison with the egg from which it 

 issues. It is light ash-gray in color, 

 the head abnormally large, and the 

 body armed with immense curved hairs 

 or spines, which give it rather a fero- 

 cious ajipearance and undoubtedly 

 make it seem to the young Psylla a ver- 

 itable dragon. It crawls down the egg- 

 stalk and begins immediately its active 

 search for food. On approaching the 

 egg or young larval Psylla, it immedi- 

 ately grasps it between its long, curved, 

 mandible-like organs, which amount to 

 two sucking tubes, between the tips of 

 which the egg or the young larva is held 

 and rolled one way and the other, as 

 between thumb and finger, the juicy 

 contents being in the meantime rapidly 

 extracted. It is a most interesting sight 

 to watch this little larva at work and 

 to note with what celerity it grasps the 

 young Psylla, quickly extracts the juices, and casts aside the dry shell, the whole 

 operation frequently taking less than a minute. 



The larva is an extremely hungry one and is always feeding, and its rapidity 

 of growth is limited only by the abundance of the food supply. It eats anything 

 that comes in its way, is totally fearless, and is also, unfortunately, cannibalistic, 

 eating its own kind with as great readiness as it does any other larva-. After 

 about ten days the larva becomes full grown, ami spins up in the curl of a leaf 

 or in any partial protection, constructing a delicate, slightly oval, but nearly 

 spherical silken cocoon, which is attached to the leaf by silken threads (tig. 4, c). 

 This cocoon is very small, in comparison with both the larva which spins it and 

 the adult which emerges from it, and is less than one-eighth of an inch in long- 

 est diameter. The adult emerges in from ten to fourteen days, cutting off the 



i. — Chrysopa ocvlata : newly-hatched larva, 

 with under side of head and claw at 

 side— greatly enlarged. 



