EGG PARASITES OF THE GIPSY MOTH. 



171 



Fig. 13.— Anastattis bifas- 

 ciatus: Uterine egg. 

 Greatly "enlarged. 

 (Original.) 



tain in the hope that laboratory reproduction could be secured was 

 soon recognized to be a mistake, and as the Anastatus continued to 

 emerge considerably ahead of the time when they would obviously 

 have issued under more natural conditions, it was resolved to remedy 

 the evil, if possible, by placing the parasitized material in cold stor- 

 age. This experiment was successful. The further 

 transformations of the parasites were retarded 

 without any apparent prejudicial effects upon 

 their vitality, and in July some 500 were reared 

 and colonized in the field. 



Coincidently with the height of their emergence 

 and subsequent to its close, a considerable number of a small black 

 encyrtid, later described by the senior author as Tyndarichus navx, 

 issued, and all were destroyed on the supposition that they might be 

 secondary. This was not by any means certain, and it was resolved to 

 investigate their habits thoroughly so soon as opportunity should offer. 



Accordingly, in the fall of 1908, 

 following the receipt of several con- 

 siderable shipments of egg masses 

 from Japan, an exhaustive investi- 

 gation of the gipsy-moth egg para- 

 sites was inaugurated. These in- 

 vestigations were more intimately 

 associated with the work upon 

 Schedius, and more will be said 

 of them in the discussion of that 

 species. So far as Anastatus was 

 concerned, its life and probable 

 habits stood revealed from the start. Almost in the beginning its 

 larvae were found (fig. 14) and identified correctly, as was later 

 proved. They were almost invariably found in eggs which had 

 been destroyed before embryonic development had taken place, 

 which showed conclusively that these eggs were attacked within a 

 very short time after their dep- 

 osition. It was known that the 

 adults did not issue until after 

 the caterpillars had hatched from 

 healthy eggs in the spring, and 

 the fact that the species was 

 single brooded, with a life cycle 

 that was correlated perfectly with 

 that of the gipsy moth, was as 

 certainly evident then as now, after two years' observation of its 

 progress in the field has given ample confirmation. 



The egg of Anastatus has not been seen after deposition, but its 

 appearance before is indicated by figure 13. The full-fed larva 



Fig. 14. — Anastatus bifasciatus: Hibernating 

 larva. Greatly enlarged. (Original.) 



Fig. 15. — Anastatus bifasciatus: Pupa from gipsy- 

 moth egg. Greatly enlarged. (Original.) 



