destructive to Barley and Turnips. 



175 



Yl\ 



This chrysalis is of an 

 oblong-oval form, not 

 quite a quarter of an 

 inch long, nearly re- 

 sembling the smooth 

 cocoon of a small moth, 

 and exhibiting no 

 traces of future limbs ; 

 but it is of a hard tex- 

 ture, of a dark reddish 

 brown colour, with 

 thirteen rather indis- 

 tinct rings, and with 

 the extremities fur- 

 nished with several 

 minute hard points. 

 I have represented it 

 highly magnified in 

 fg, 1 7. a. Now, from 

 analogy, we are en- 

 abled to state, that this 

 chrysalis is not the 

 pupa state of Mr. 

 Farmer's turnip insect 

 (e, nat. size ; f 9 magni- 

 fied), because the latter 

 belongs to a family which, in that state, is destitute of any cover- 

 ing, lying in its cell or gall, with all its future limbs perfectly 

 distinct. Until I had more minutely examined this chrysalis, I 

 thought that it might be the cocoon of the ichneumon, as some 

 of that family do spin silken cocoons, and that Mr. Farmer 

 had confounded the two insects ; but, on magnifying it, I found 

 that it does not belong to either of them ; that it was the im- 

 mature state of a dipterous insect, being the covering of the 

 real pupa, formed of the indurated skin of the larva, that the 

 insect wa> consequently undergoing the coarctate kind of 

 metamorphosis. Moreover, from its general structure, it ap- 

 pears to I elong to one of the fly tribe, ikfuscidae. Fig, 17- b 

 represent: a horny process inside the skin, which had formed 

 the head ui the larva, and which remained attached after the 

 enclosed insect, figured in a highly magnified state at c 9 had 

 become a pupa, and which is of a white colour, with large 

 eyes, a rounded forehead, and two minute lateral rudimental 

 antennae. On each side behind the eyes, a dark-coloured 

 spot is seen, figured at d 9 having several oval tubercles of a 

 very minute size, and which seem to protect a pair of spira- 



