216 



PARASITES OF GTPSY AND BROWN-TAIL MOTHS. 



characters in the fall. The space between the pupa or nymph and 

 the shell of the puparium is filled by a small quantity of liquid, and 

 the complete drying up of this liquid is very prejudical to the health 

 of the individual, and is usually sufficient to prevent its emergence. 

 The difficulties which have stood in the way of a successful intro- 

 duction of Blepharipa scutellata into America have differed in many 

 respects from those which have accompanied the work with any of 

 the other species, saving only the closely allied Crossocosmia. The 

 first importations of full-grown caterpillars or freshly-formed pupge 

 of the gipsy moth in 1905 resulted in the securing of a considerable 

 number of hibernating pup aria. There were several hundred at least, 

 but although they were kept under conditions which would be satis- 

 factory in the case of most of the tachinids, not a single Blepharipa 

 issued in the spring of 1906. The death of the insect did not take 



place until after the fly was 

 fully formed and apparently 

 nearly ready to issue from the 

 puparium. 



A great many different 

 methods of hibernating these 

 pup aria have been experi- 

 mented with at the laboratory 

 with variable, and until the 

 winter of 1909 with poor, re- 

 sults. During the winter of 

 1907-8 the puparia were kept 

 in moist earth and a IP per 

 cent emergence from a total of 5,000 was secured. The year before 

 they were also hibernated in earth, but the emergence was less, 

 amounting to only 3 per cent of the total, and the year following 

 still less, being only about 1 per cent. 



In 1909 for the first time since the inception of the work large num- 

 bers of living gipsy-moth pupa? containing the immature maggots of 

 Blepharipa were received at the laboratory from Hyeres, France, 

 through the magnificent efforts of M. Rene Oberthur, of Rennes, and 

 as a direct result of the senior author's trip earlier the same 3^ear. 

 Some idea of the size of these shipments may be gained by reference 

 to Plate XIX, figures 1 and 2, which show a small proportion of the 

 total number of packages at the time of their receipt at the laboratory. 

 For the first time it was possible to allow the formation of the puparia 

 under natural conditions in the earth. During each of the preceding 

 years the caterpillars and pupae had been received from abroad by 

 means of the ordinary methods of transportation and puparia had 

 been formed in the boxes on receipt. They were often injured and 

 always thoroughly dried when received. This year provision had 



Fig. 40. — Blepharipa scutellata: Basal portion of tracheal 

 "funnel." Greatly enlarged. (Original.) 



