326 INSECT TRANSFOPaiATIONS. 



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 gnawing through the 

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

 into the seeds themselves and the chaff 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 proceed- 

 ings of the insect may be easily examined. t 



A similar prospective contrivance occurs in the 

 instance of a caterpillar which feeds on the cow 

 parsnip (Heracleum spondylium'). and makes a cir- 

 cular 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 

 pupse 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 {Tifulce oleracea;?) 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 Hies 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. f J. R. 



