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be several times that of the insect, rapidly increasing until it forms a 
good- sized drop. This, when there are millions to aid in the work, 
soon becomes abundant enough to fall as a shower from the tree when- 
ever it is shaken by the wind or other means. Mr. Slingerland shows that 
there are 5 molts, including the last change from the pupa to the adult 
insect, and the life from the laying of the egg to the adult covers a 
period of about thirty days, the periods between molts varying from 
three to seven days. In Maryland, the second brood, as indicated, 
had already entirely transformed to the adult stage by the 21st of 
July, and allowing a month for a generation to include the egg period, 
we ought to expect a third brood of adults about the first of Septem- 
ber, which will probably be the hibernating brood. 1 
NATURAL ENEMIES. 
No enemy for this insect among the parasitic and predaceous species 
has hitherto been recorded. On my first visit to fche orchard of Mr. 
Emory I was shown what was taken to be the egg of the Psylla, which 
proved, however, to be the egg of a common lace-winged fly, Chrysopa 
oculata Say. The mistake was a very natural one, because the eggs 
occurred in such extraordinary numbers throughout the orchard. On 
some trees nearly every leaf would have one or two eggs of the Chry- 
sopa attached to it. I immediately inferred that the abundance of the 
Chrysopa was an incident of the extraordinary multiplication of the 
Psyllas, and recognized that the latter had a very important enemy 
in the larva of the lace winged fly. At this visit I did not have time 
to investigate the matter further, but on the second visit nearly full- 
grown larvae of the Chrysopa were found on the pear trees attacking 
and devouring the adult Psylla in a very vigorous manner. I collected 
a large quantity of the Chrysopa eggs and bred a number of young 
larvae, and found that they would feed with great readiness on both the 
eggs and the young larval Psyllas. 2 I think it a safe estimate to say 
that one lace- wing fly larva will easily destroy several hundred eggs 
and larvae of the Psylla in addition to the adults which it will destroy 
in its later larval growth. From the great numbers of the Chrysopa 
eggs on the pear trees it is not at all improbable that the lace- winged 
fly alone will bring the Psylla pretty well into subjection. 
Two or three species of ladybirds were also observed running about 
over the pear trees, the commonest one being Adalia bipunctata L., a 
little red species with two black spots on its elytra. One of these latter 
species was seen in the orchard with an adult Psylla in its mandibles, 
and in my breeding cage at Washington one or two adults cleaned the 
Numerous belated species of the July brood were caged on potted pear trees Aug. 
3 and produced a new brood of adults by Aug. 30 and these still another by Oct. 1. 
None of these, even of the last brood, showed any variation from the summer form. 
■On some trees that were infested with a Phytoptus sp., allied to the pear-leaf 
blister-mite, but living exposed ou the lower surface of the leaves, the Chrysopa 
larvte were observed also to devour the mites of this species with great avidity. 
