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 host. In the course of this search they will enter the damp 



