On the Pupation of Cossus Ligniperda. 



By Robert Adkin. Read February 22nd, 1900. 



For some years I had scented " Goats " in the neighbourhood of 

 some rather dilapidated poplar trees that grow within the low fence 

 of a garden adjacent to my home, and which I pass almost daily. 

 Indeed, on one occasion I found a straying larva of the species on 

 the pavement in front of the said fence, and on another an imago 

 resting on the fence, but it was not until last summer that I fairly 

 " came up with the herd." I was then fortunate in meeting with 

 a considerable number of imagines, in batches of from one to four 

 or five at a time, on various evenings between June 24th and July 

 1 8th, resting on the fence with wings still limp, and in almost every 

 case I was able to find the empty ])upse skins from which they 

 had just emerged, and was thus able to ascertain the exact situa- 

 tion where pupation had taken place. Taking them, or rather 

 such of them as one cared to take — for my available setting space 

 for such large insects would not accommodate all that I saw— was 

 quite an interesting adventure. To box such fine fellows while 

 their wings were limp would have been simply wanton destruction. 

 I therefore hit upon the plan of inducing them to walk on to my 

 coat sleeve, which they did readily enough, and soon settled them- 

 selves on some part of my clothing that appeared suitable to them, 

 and were thus conveyed home without injury. No doubt I pre- 

 sented a picturesque appearance to my neighbours, but that was a 

 matter of slight importance, considering that my chief object was 

 satisfactorily attained. On reaching home a very slight amount of 

 persuasion induced them to transfer themselves from my coat to 

 the net curtains in front of an open window, where they rested 

 quietly until their wings were fully hardened. In this way I secured 

 many very fine specimens, and lost very few — one only, if I remem- 

 ber rightly. But I fear I am wandering somewhat from my subject, 

 viz. the method of pupation. 



If we consult the older authors we find, I think, without exception, 

 if the matter is touched upon at all, that they took it for granted that 

 the larva lived on the hard wood of the tree in which it burrowed, 

 and when full-fed spun its pupal cocoon at the " entrance " to the 

 burrow. Moses Harris, who wrote just over a century ago, gives the 

 following detailed account of the habits of the species, which is 

 perhaps as lucid a description as any to be found in the works of 

 that period : 



" The caterpillar feeds on the wood within the body of the willow 

 tree ; also on oak. It is not full-fed until the third year after it 

 comes from the egti. When ready for transformation they spin a 



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