254 [November, 



themselves, and by the following morning all were free. They made 

 no attempt to crawl, having, indeed, no legs, but a few, by some 

 wriggling process, managed to remove themselves about half an inch, 

 after which there was no more locomotion. They all began to dis- 

 charge from their bodies a round mass of dark green excrement, 

 evidently the whole of their colouring matter, for each one, as soon as 

 this ])urgation was accomplished, ceased to be green, and became 

 yellowish-white, the usual colour of maggots. Thus they remained 

 during August 21st. On the 22nd, at different hours, they all moulted, 

 and appeared as delicate white pupae (fig. 3), lying on their backs, 

 unprotected by any cocoons, and now showing the whole Hymeno- 

 pterous structure of antennae, legs, &c., packed into the smallest 

 compass. A change of colour now rapidly supervened, the white 

 passing in a few hours into grey, and finally into deep black. In this 

 state they remained, lying about at random, till September 1 Ith, when 

 two assumed the perfect state. On September I2th the others fol- 

 lowed their example, and I found myself in possession of thirteen 

 Chnlcids (fig. 4), all females, and exactly alike. My efforts to deter- 

 mine their species were not successful, but I pursued them through 

 Forster's tables till I arrived with much certainty at the genus 

 Pferomahis ; as this contains an undigested and indigestible mass of 

 hundreds of species, I could go no farther. All I can say is that my 

 specimens have the common features of the genus, and are not far 

 from P. patulus, Walk , one of the few which I have got named. If 

 any gentleman in this or any other country can name the species I 

 shall be happy to give him specimens. What seems chiefly remarkable 

 (apart from the fact of external parasitism) is the absence of all 

 covering or protection for these naked and helpless larvae during their 

 changes. Jf I had left them on their native tree, they must inevitably, 

 on the death of the caterpillar, have fallen a distance of some feet on 

 to the bare ground, and there remained exposed, without power to 

 make cocoons or to burrow into the earth. It is also curious to 

 observe the precise coincidence, in point of time, of the death of the 

 victim and the maturity of the parasites, so that the supply of food 

 ceased exactly when it was no longer required ; if there had been 

 four or five more parasites, the caterpillar would have been exhausted 

 too soon, and the supply of nourishment would have failed before the 

 parasites were completely grown. Instinct, or nature, has here pro- 

 vided some very nice adjustments to adapt variable means to a fixed 

 end. 



Botusfleming Eectory, Cornwall : 

 September 23rd, ls95. 



