IMPORTATION AND HANDLING OF PARASITE MATERIAL. 157 



opening large enough to accommodate the head. No special pro- 

 vision for ventilation is necessary, but it is necessary to construct 

 the boxes of soft and absorbent wood in order to secure best results. 

 This will not only prevent too rapid evaporation, but superfluous 

 moisture will first be absorbed and subsequently will evaporate. 

 Tin boxes are wholly unsuitable and paper or pasteboard have never 

 been at all satisfactory. 



Twigs with foliage should be included in each box, and these must 

 be long enough to remain firmly braced in case the caterpillars eat 

 the foliage. Some very bad results have followed the use of loose 

 foliage, a practice which certain collectors have been persistent in 

 following. 



The fewer the caterpillars included in each box the better the 

 results. The number has gradually been reduced from 100 at first 

 to 20 during the past few years. Undoubtedly 10 would be better 

 yet, but not enough better to make the added expense an economy. 



The more nearly the caterpillars are ready to pupate when packed 

 the better. If collected just a few days before pupation, they usually 

 arrive in good shape, provided conditions otherwise are as they 

 should be. 



Shipments by mail have generally been successful when the boxes 

 were not smashed, as has sometimes happened, or when something 

 else was not wrong. Shipments by express without cold storage 

 have been equally successful when the boxes have been properly 

 packed. As has been said, there is no need to provide for the ven- 

 tilation of the interior of the box, but the exterior must be exposed 

 to the air on at least one side to permit the evaporation of the mois- 

 ture absorbed by the wood. Otherwise, as nearly always happens, 

 when a part of the caterpillars or pupae die, they decompose, and as a 

 result of their presence a similar fate usually overtakes the remainder. 

 Some very large shipments were a complete loss in 1907, merely 

 because a European agent, prevented by newly enforced postal 

 regulations from making shipments by mail, packed the boxes tightly 

 in large packing cases and forwarded them by express. When the 

 lids were removed from these cases the sides of the boxes were found 

 to be thoroughly damp, and the whole exhaled an ammoniacal odor 

 so strong that it would seem of itself alone sufficient to destroy any 

 ordinary form of insect life. 



Bundles of boxes wrapped in thick, glazed paper have almost invari- 

 ably been received in bad condition. If the paper is soft and absorbent 

 it is generally satisfactory. One collector wrapped several packages 

 in a thick fabric composed of tarred paper strengthened by muslin, 

 and the contents rotted. 



Cold storage in the case of shipments of this character would never 

 have been either necessary or even desirable had it not been for the 



