10(5 [October, 



This year I have reared several hundreds of the caterpillars o£ 

 JPiei^is brassicce, and, after cutting the loops and making them hang by 

 the tail like Suspensi, I have watched their subsequent exclusion. 

 Some 200 succeeded in fixing their tails in the silk, and remained sus- 

 pended ; while about 150, after a few oninutes' endeavour, fell down, 

 having failed to reach the silk with their hooks ; some difference in 

 the relative length of the tail and membrane probably determining the 

 result. In some of the batches as many as two-thirds were successful 

 in hooking themselves on by the tails, and I have no doubt, with more 

 careful management, the proportion would be still higher. In several 

 instances these Fieris caterpillars spun a double loop. I enclose a 

 pupa of one of these. 



Is not this membrane a persistent and specialized portion of the 

 general subcutaneous connective tissue ? persistent in part, as Dr. 

 Chapman observes, for want of a point d'appui from which to act upon 

 it before the tail of the chrysalis is fixed. In that case one would 

 look for it, or something like it, even where no such purpose could be 

 served by it as in the case of the Suspensi. Last year I watched the 

 pupation of a small beetle {Gastrojihysa rajjhani) in a great many 

 instances, and found that it occupied very nearly about twelve minutes. 

 But, whilst the puj^a was completely excluded in about six minutes, 

 something held the old skin so firmly to the tail of the pupa, that 

 the rest of the twelve minutes was occupied in getting rid of it alto- 

 gether. The old skin was not merely resting there, or adherent to a 

 hair, but firmly attached, and not to be removed by a camel's hair 

 brush. Of course, in the natural circumstances, where the insect 

 would have crept under dead leaves or grass when fed up, and could 

 have acted against these, it might have been able to rid itself sooner 

 of the exuviae. 



Milford, Letterkenny : 



September, 1878. 



[We have forwarded to Dr. Chapman the preparations above 

 referred to. — Eds.] . 



Pieris rapm attacked hy Microgaster. — BelieTing that the exhibition by Mr. Boyd of 

 a larva of Pieris rapce attacked by Microgaster, at a Meeting of the Ent. Soc. on 

 November Vth, 1877, is the only evidence brought forward of that parasitism, I 

 beg to say that I have to-day found a slirunken larva of the butterfly surrounded by 

 some twenty cocoons of the familiar parasite. 



I have this month bred several specimens of a Chalcid from a pupa of P. rapa; ; 

 and have, in former years, bred many specimens of a Tachina from pupae of the same 

 butterfly. 



