154 PARASITES OF GIPSY AND BKOWN-TAIL MOTHS. 



GIPSY-MOTH CATERPILLARS, SECOND TO FIFTH STAGES. 



EUROPEAN IMPORTATIONS. 



The first importations of gipsy-moth caterpillars in the second to 

 fifth stages were made in 1907. Small wooden boxes, each with a 

 capacity of about 40 cubic inches, were used for the purpose, and 

 all shipments were by mail. The caterpillars, usually to the number 

 of 100, were inclosed in these boxes, together with several twigs 

 bearing fresh foliage. 



The method was of doubtful utility, and at the same time no 

 improvement upon it could be devised short of cold storage en route. 

 On receipt the twigs would usually be stripped bare of foliage. Some 

 of the caterpillars were invariably dead — whether from starvation or 

 from injuries received at the time of collection or subsequently could 

 not be determined. The remaining caterpillars were in all stages of 

 emaciation and many of them, though still living, were too weak to 

 recuperate. 



Parasites in considerable variety but always in very small num- 

 bers issued, for the most part en route, but occasionally from the 

 caterpillars after receipt. Nothing could be decided as a result of 

 these importations and their repetition was resolved upon. 



It was planned to import much larger numbers in 1908 without 

 modifying the methods employed the year before. In this respect 

 success was not achieved, principally, it would appear, on account of 

 the difficulty of collecting these small caterpillars in numbers, espe- 

 cially in localities where the gipsy moth was not very abundant. 

 Furthermore, it became increasingly evident that the percentage of 

 parasitism (so far as it could be determined by the actual number of 

 parasites secured) was so insignificant as to make the task of import- 

 ing sufficiently large numbers of any one parasite for the purpose of 

 colonization wholly impracticable. Many of the lots of caterpillars 

 winch were received in the best condition produced no parasites at 

 all. It was therefore evident that if extensive operations in any 

 locality should be determined upon, complete failure might result 

 through the absence of the parasites in that particular locality dur- 

 ing that particular season. Nothing less than an improvement in 

 the service of several thousand per cent over that of 1907 or 1908 

 would answer, and this was altogether out of the question, except 

 at an expenditure which even the generous funds appropriated by the 

 State and Federal Governments could not cover. Further importa- 

 tions from Europe were regretfully decided to be impracticable. 



