210 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
of similar material was received from an even greater number of 
localities in 1907, and a smaller, but still a considerable amount in 
the course of the year following, and no trace of Melittobia was 
encountered, it began to become apparent that the quite general 
infestation of the puparia in 1906 had taken place after their receipt 
at the laboratory. 
Vigilance unrewarded during the two years slackened somewhat 
in 1909, and late in the summer a new infestation of Melittobia 
suddenly developed. Where it originated was and remains wholly a 
mystery. Possibly the first individuals were received in a large 
shipment of sarcophagid puparia which had been collected in Russia 
and forwarded to the laboratory by Mr. Kincaid, who considered 
them to be gipsy-moth parasites. This lot of several thousand 
puparia was thoroughly infested, and a very large proportion con- 
tained either the exit holes or the brood of Melittobia when their 
condition was discovered. 
But the infestation did not stop here. Various small lots of puparia 
of various sorts, inclosed in small pasteboard boxes, in cloth-covered 
vials, or in other receptacles were found to have been attacked by 
the parasite. It seemed suddenly to have come from nowhere and 
to have attacked everything at once. 
Avery general cleaning up was immediately instituted, but again, 
it was felt, after the damage had been done. The sarcophagid 
puparia, which would otherwise have served as the basis for a very 
necessary and desirable series of investigations into the true char- 
acter of these flies, had to be destroyed. A large percentage of 
them was attacked by the parasite, and the rearing of the healthy 
remainder involved the isolation of each and all of them in a series 
of tightly stoppered vials. The Melittobia were issuing daily and 
immediately attacking the healthy remainder and there was no 
method short of breaking open each puparium which sufficed to 
determine its condition. 
After the cleaning up had been accomplished, Mr. Smith began a 
series of investigations into the life and habits of the parasite, the 
results of which he intended to have prepared for publication before 
leaving the laboratory. Since he did not do this, and since the 
species is one which is likely to become a cause of annoyance should 
similar work to the present be undertaken, the following brief sum- 
mary of the results of his studies may be given. 
The minute females, after having been fertilized by the still more 
minute, blind, and wingless males, issue from the puparium in which 
they have passed their early transformations and go in quest of others 
which they may attack. They will also attack hymenopterous co- 
coons, but with less success, apparently, than in the case of the more 
favored bost. In the course of this search they will enter the damp 
