SURROUNDINGS OF GROWING INSECTS 223 



modified tracheal tubes with their tail-spiracles just within 

 the opening of one of the caterpillar's spiracles (Fig. in d). 

 This parasite usually allows its host to pupate ; then it 



a. Larvae of Ichneumonoid (Apantelcs fulvipes) eating " Gipsy " caterpillar, x ij. b, cocoons 

 of Apanteles surrounding dead caterpillar, slightly enlarged, c, cocoons from which Apantele. 

 (a) and its various secondary parasites (6, c, d, e) have emerged, x 2. From Howard and Fiske. 



devours the pupa internally, becomes full-grown, and itself 

 pupates in the soil. 



Of the hymenopterous parasites of insect-larvae, the most 



