DISEASE$ OF INSECTS. 225 



tack of these parasites. Where larvae and pupae are 

 aquatic, it seems probable, if any attack is made upon 

 them, that it must take place after they have quitted the 

 water. 



In the Hymenoptera Order itself, almost every genus 

 has been ascertained to have its Ichneumon parasites. 

 Not even the fortified habitations of the gall-flies (Cy- 

 nips) can escape them, almost every species becoming 

 their prey; a circumstance which puzzled not a little 

 some of the older naturalists, when they at one time saw 

 a fly not remarkable for its colours or brilliancy emerge 

 from the curious moss-like Bedeguar of the wild rose, 

 and at another were struck by the appearance of one of 

 those splendid minims of nature which almost dazzle the 

 sight of the beholder a . Immunity, however, from this 

 pest seems to have been granted to the gregarious Hy- 

 menoptera ; at least none has yet been discovered to at- 

 tack the ant, the wasp, the humble-bee, or the hive-bee ; 

 in which last, had there been one appropriated to it, it 

 could never have escaped the notice of the Reaumurs 

 and the Hubers. The solitary bees, however, as we 

 have seen above b , do not escape ; and Epipona spinipes, 

 a solitary wasp which feeds its own young with a number 

 of green caterpillars c , is itself, when a larva, though 

 concealed in a deep burrow, the prey of the grub of an 

 Ichneumon, which by means of a long ovipositor intro- 

 duces its egg into its body d . Even these parasites, 

 whose universal office it is in their first state to prey 

 upon insects, are themselves subject to the same malady. 

 Ichneumonidan devourers are kept in check by other 



a Rai. Hist. Ins. 259. b See above, p. 21 7 ; and VOL. I. p. 356. 

 c Ibid. 348. d Reaum. vi. 303- . 



VOL, IV. O 



