181 



t^ggs from the leaves of a youug pear tree about as fast as upward of 50 

 to 75 Psyllas laid tbeni. The larvie of the ladybirds are equally active 

 and beneflcial, and I had no difficulty in rearing a brood from the eggs 

 in my breeding cages on the eggs and larvie of the Psylla. 



It is possible that the disaijpearance of the Psylla in the orchard of 

 Mr. Brown may have been in part due to the attacks of these two pre- 

 daceous enemies, but while the great value of these two insects, 

 particularly of the lace-winged fly larva^, in this direction can not be 

 questioned, they could hardly have caused complete extermination 

 which has probably been more correctly accounted for above. 



LIFE HISTORY OF THE LACE-WING FLY. 



The predaceous habits of the lace-wing fly larva? are of common 

 record, and their beneficial character is well known, but in view of the 

 important role played by this insect in the economy of the Psylla it is 

 of interest to describe more minutely its life history and habits. The 

 eggs, instead of being deposited in rather numerously 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 stalk is also not half the usual length, not much exceeding 

 three times the length of the egg proper. Judging from examinations 

 made on my first and se(;ond visits, 1 should say that the egg period 

 ranged from seven to ten days. The young larva cuts ofi" the upper 

 end of the egg on emerging and is surprisingly large in comparison 

 with the egg from which it emerges. It is light ash-gray in color, the 

 head abnormally large, and the body armed with immense curved hairs 

 or si)ines which give it rather a ferocious appearance and makes it 

 seem to the young Psylla undoubtedly as a veritable dragon. The 

 body is long and tapers very considerably toward the tip, and the head 

 is notable for what appear to be two large curved mandibles. It crawls 

 down along the egg stalk and begins immediately its active search for 

 food. On approaching the egg or young larval Psylla it immediately 

 grasps it between its long curved mandibles. These are really com- 

 pound organs, being deeply grooved to inclose the maxilhi?, which 

 nearly equal in size, are of similar form, and play in the grooves of the 

 mandibles. These organs form 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 a thumb and finger, the juicy contents being in the 

 meanwhile 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 taking frequently less than a minute. The larva 

 is an extremely hungry one, is always feeding, and its rapidity in 

 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, unfort- 

 unately, cannibalistic, eating its own kind with as great readiness as 



