326 INSECT TRANSFORMATIONS. 



tion.* But we have only to examine the arrange- 

 ment of the teazle seeds to perceive that he must 

 have been mistaken. In a dozen specimens now 

 before us we find that, besides knawing through the 

 wall, the insect has eaten about an eigth of an inch 

 into the seeds themselves and the chatf which sur- 

 rounds them, leaving on the outside the extremities 

 untouched, but lining the whole with a slight tissue 

 of silk, — the circumstance, no doubt, which misled 

 Bonnet. As these are extremely common in the 

 vicinity of London, almost two-thirds of the seed 

 heads of teazle containing a caterpillar, the pro- 

 ceedings of the insect may be easily examined. t 



A similar prospective contrivance occurs in the in- 

 stance of a caterpillar which feeds on the cow parsnip 

 {Hercicleum spondylium), and makes a circular hole 

 in the stem for the exit of the moth. 



In all the preceding instances, the pupa is left; to 

 effect its extrication by its own unassisted efforts. 

 But amidst the variety which claims our admiration 

 in the economy of insects, we have to notice pro- 

 ceedings no less remarkable in the case of those 

 pupae which require extraneous assistance in their 

 transformations. An instance of this is mentioned 

 by Kirby and Spence, on the authority of the Hon. 

 Captain Percy, R. N., who, while he was watching 

 some female crane flies {Tipiilxc olcraccce?) busily 

 employed in depositing their eggs amongst the roots 

 of grass, saw one quitting her pupa case. She had 

 already, by her own efforts, got her head, shoulders, 

 and fore-legs disengaged, when two male flies arrived 

 to assist in her extrication. They immediately laid 

 hold of her pupa case with their anal forceps and hind- 

 legs, while with their fore-legs and mouths they 

 seemed to push her upwards, moving her backwards 



* Bonnet, CEuvres, vol. ii, obs. xix. t J. R, 



