552 



HYMENOPTERA 



frequently covered with a highly-developed sculpture. The hind 

 body springs from the lower part of the propodeum ; it is usually 

 of slender form, and its segmentation is very conspicuous. The 

 females bear an ovipositor, which differs greatly in length accord- 

 ing to the species, and is known in the case of one species to 

 attain a length six times that of the whole of the rest of the 

 body. 1 The egg is deposited by some species on the skin, by 

 others within the body of the victim ; it varies much in form and 

 colour, some eggs being stalked and of peculiar shape. The 

 larvae issuing from the eggs are legless maggots with a delicate 

 integument of pallid white or creamy colour. If the eggs are laid 



on the surface of the body, the result- 

 ing larvae (except in the cases of the 

 external parasites) soon bore into the 

 interior of their victim, and disappear 

 therein. The changes that take place 

 in the lifetime of the larvae have 

 been studied in only a few cases ; but 

 if we can judge from Ratzeburg's 

 history 2 of the changes that take 

 place in Anomalon, they are of great 

 interest. From observation of the 

 differences existing amongst a great 

 number of larvae of A. circumflexum 

 he distinguished four stages. It is of 

 course impossible to follow directly 

 the growth of one individual, be- 

 cause it is concealed in the interior 

 of the caterpillar in which it lives, 

 and to open this involves the death 

 of both caterpillar and Ichneumon- 

 larva. The life history must therefore 

 be constructed from a great number of 

 instar;B second instar ; c, the separate observations; and it is not 



larva in the third or encysted c 



stage extracted from its cyst ; ascertained that the four instars de- 



D, the mature larva ; E, pupa. ^.^ by Ratzebm>g re p res ent the 



number of moults of the larva that actually take place. He, 

 however, entertained no doubt that all the forms he observed 



FIQ. 361. Anomalon circum- 

 flexum, larval development. 

 (After Ratzelmrg. ) A, First 



1 Tosquinet, Ann. Soc. ent. Belgique, xxxviii. 1894, p. 694. 

 2 Ichncum. Forst. Ins. 1844, p. 81. 



