IMPORTATION AND HANDLING OF PARASITE MATERIAL. 163 



en route, and the cocoons are so strong as to prevent the pupa3 from 

 becoming injured. 



There has never been any trouble experienced through these boxes 

 sweating en route, as has so frequently happened when boxes con- 

 taining gipsy-moth caterpillars have been too closely confined in box 

 or bundle, but at the same time those which have been exposed to 

 free circulation exteriorly are noticeably in better condition than 

 others. 



Much the larger proportion of the material of this sort has been 

 received in perfect condition at the laboratory, and large quantities 

 of parasites have been reared from nearly every lot thus received. 

 Occasionally boxes have been used which were not sufficiently tight 

 to prevent the escape of the tachinid larvae, and some loss has accrued 

 in consequence. In a number of instances the boxes have been 

 infected with fungous disease, and all or nearly all of the caterpillars 

 or freshly formed pupae have died in consequence. In rather an 

 unnecessary number of instances, or so it would seem, caterpillars 

 have been collected too young, and have failed to pupate en route. 

 Such shipments properly fall in the class last mentioned, and are 

 worthless for the purposes desired. 



Through a misunderstanding nearly all of this class of material 

 was sent in cold storage in 1909, with the result that the caterpillars 

 failed to pupate en route, as. would have been the result otherwise, 

 and a good many of them failed to pupate after receipt. Considera- 

 ble loss resulted on this account before the collectors could be noti- 

 fied to return to the original method of shipping by mail. 



In handling the boxes of caterpillars and pupae, a variety of meth- 

 ods has been employed, of which the most satisfactory appears to be 

 simply boring a hole in the one end, and introducing a paper cone 

 and tube. Even the removal of the covers from a dozen or more 

 boxes without protection is accompanied by painful results, and 

 owing to the difficulty of boring the holes without splitting the wood, 

 after the box has been received at the laboratory, collectors are now 

 instructed to prepare the boxes for the reception of the tube at the 

 time of their manufacture. 



In 1906 and 1907, when the first shipments of this character were 

 received, and when little was known of the character of the parasites 

 which were likely to be reared from them, it was thought necessary 

 not only to open each box, but to sort it over, and remove the tachi- 

 nid puparia which were always present in a larger or smaller number. 

 It was known that there were always present certain species of tachi- 

 nids which would only complete their final transformations success- 

 fully when their puparia were kept more or less moist, and it was 

 expected that among the parasites of the brown-tail moth would be 

 some possessing this characteristic. Opening the boxes without some 



