156 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



insignificant numbers, which could not he secured much more easily 

 in other ways, and no further importations were attempted in 1909. 



Relatively such small quantities of this class of material have been 

 received as to make unnecessary any specialty devised methods for 

 their economical handling. With very few exceptions the boxes were 

 opened immediately upon receipt and most carefully sorted for parasites 

 and Irving caterpillars. A few of the large Japanese boxes were not 

 opened immediately, but holes were bored in the end, cones and tubes 

 inserted, and living insects of all sorts thus attracted to the light and 

 removed. The living caterpillars were placed in cages or trays and 

 fed, and occasionally a few parasites were thus secured in addition 

 to those present in the boxes upon receipt. 



It is very much to be regretted that the dead and dying cater- 

 pillars were not preserved for subsequent examination and dissection, 

 but it was only in 1909, after the shipments of this sort of material 

 had been discontinued, that the wholesale dissection of caterpillars 

 was attempted for the purpose of ascertaining the proportion of 

 parasitized individuals. At the best, even after long experience, it is 

 a. tedious process, especially in the case of material which has been 

 killed and preserved. 



A few caterpillars, accidentally imported in their early stages with 

 Apanteles cocoons in 1910, were saved and dissected with good results 

 from a technical standpoint. 



GIPSY-MOTH CATERPILLARS, FULL-FED AND PUPATING. 



Importations of large caterpillars (PI. VI) ready or nearly ready 

 to pupate were first made in 1905, and it was demonstrated during 

 that year that they could be brought to America with a fair degree 

 of success, and that at least a proportion of the parasites with which 

 they were infested could be reared. 



Ever since 1905 we have been attempting to improve upon the 

 methods first used during that year and have experimented with 

 scores of modifications of the most successful, some of which were 

 intentional while others were incidental to the fact that there have 

 been many different collectors, each of whom has displayed some 

 individuality in his methods of collecting and packing. It would 

 be tedious and is probably unnecessary to go into detailed de- 

 scriptions of even a part of these various intentional or accidental 

 experiments. 



The most successful method yet devised involves the use of rather 

 shallow wooden boxes having a capacity of from 40 to 70 cubic 

 inches. (See PL VIII, fig. 3.) Quite a large number of shipments 

 has been made in much larger boxes, but their condition on receipt has 

 almost invariably been very bad. The boxes must be tight to prevent 

 the escape of tachinid larvae, which can apparently pass through any 



