APHID170K0US lOHNEUMONID^. 151 



lation of sap in these vegetable monstrosities is one 

 cause of the curious localization of such different 

 insects. 



This family of gall-makers has straight, non-flagellate 

 antennae, each composed of from thirteen to fifteen 

 joints. The ovipositor is sub- spiral and internal. The 

 wings are comparatively simple in character and have 

 but few nervures. The males, where such have been 

 discovered, show one or two antennal joints in excess 

 of the females. 



ApHIDIVOROUS ICHNEUMONID^. 



This section was constructed by Leach out of the 

 large group indicated by Linneus. Most of the 

 members are notable for the extraordinary quasi intel- 

 ligence they show in constructing their cells, and 

 storing them with animal food of various kinds for 

 the use of their young and footless larvae. The 

 somewhat fanciful but expressive appellation of the 

 family relates to the fabulous habit of the quadruped 

 of that name, which formerly was supposed to deposit 

 its young in the open mouth of the sleeping crocodile, 

 from whence it proceeded to eat its way out to liberty 

 through the entrails of the reptile. 



Although the Ichneumonidse chiefly prey upon the 

 Lepidoptera, they attack other orders of insects. Even 

 the chitinous coverings of the Coleoptera are not 

 proof against the penetration of the ovipositors of 

 some species. Westwood has figured an Ichneumon 

 ovipositing in the larva of a Syrphus, whilst the latter 

 was in the very act of extracting the juices from a 

 living Aphis. 



Those Ichneumons which attack Aphides are minute, 

 and are often hardly larger than their victims. Such 

 may be considered as the least highly developed mem- 

 bers of the family.* 



* For a digest of this section of tlie Ichneumonidae tlie reader cannot 

 be referred to a better autliority than Westwood's ' Introduction,' 

 &c.„ pp. 125, 137, 155, 191. 



