256 



ANIMAL PARASITES AND MESSMATES. 



alone sacrifices her liberty, and changes her form entirely 

 in order to secure the preservation of her posterity. 



The insects called Strepsiptera, which live as parasites 

 on wasps, furnish a curious example of this (Fig. 77). 

 These insects, the Polistes, the Andrense, and the Halicti, 

 do not kill the larvse of the Hymenoptera on which they 

 feed; they suck the blood of their victim slowly, and 

 leave him just enough strength "to go through his meta- 

 morphoses. The females, are condemned to remain 

 almost completely immovable on their prey, while the 

 males are winged. 



Naturalists have paid great attention to these latter 

 insects, as much on account of their mode of life as of the 

 difficulties which they have suggested to entomologists in 

 the appreciation of their natural affinities. Are they 

 coleoptera, as was for a long time, and perhaps correctly, 



supposed, or do they 

 form 'a distinct order 

 by themselves ? How- 

 ever this may be, these 

 are the facts known 

 concerning them, ac- 

 cording to the recent 

 observations of Mons. 

 Chapmann, a con- 

 scientious naturalist. 

 The females do not 

 lay their eggs in the 

 nests of wasps, but the 

 lame, under the form of meloe, penetrate into the cells, 

 by the assistance of the larvse of the wasps, which carry 

 them hidden between the second and third ring. The 



Tig. 77.— Stylops. Male, natural size, and 

 magnified. 



