242 THE SPICULTFERA. 



of these. This may constantly be observed in the 

 caterpillars of our common Cabbage Butterfly, which 

 are very frequently infested by numerous larvae of a 

 minute black Ichneumon (Microgaster glomeratus) . 

 The little agglomerations of pupae formed by this 

 parasite may often be seen attached to sheltered situ- 

 ations, such as the tops of windows and doorways, 

 the lower surface of window-sills, and other projections 

 on the outside of houses, garden-walls or palings, 

 these being usually selected by the caterpillar on 

 whose substance they have been nourished, for under- 

 going its transformations. 



Observations upon the parasitism of these insects 

 upon others in the pupa or perfect state are still 

 rather rare, but they are sufficient to show that even 

 in these conditions insects are not exempt from the 

 attacks of their merciless little foes. Several in- 

 stances of the emergence of the larvae of species of 

 this tribe from the bodies of perfect Coleopterous in- 

 sects are recorded by different authors, and I possess 

 a specimen of Timarcha lavigata, from which the 

 larvae of a small species of Bracon escaped from the 

 posterior extremity of the abdomen in such numbers, 

 as to cover the whole bottom of a pill-box an inch 

 in diameter with their little cocoons. There could 

 hardly have been fewer than a hundred of them, and 

 the beetle, as might be expected, did not long survive 

 such an unpleasant operation. 



Although the larvae of most of these insects are, as 

 above described, internal parasites, there are some 

 species (such as those of the genus Ophion, distin- 

 guished by its exceedingly compressed and truncated 

 abdomen, and the absence of the small triangular cell 

 of the disc of the wing) whose larvae never penetrate 



