1877.! 201 



examined with a lens the inside of the gall, and satisfied myself that 

 this larva was its only inmate ; and I may further add that the saw-fly 

 larvae in the galls on the same willow-bush from which the specimen in 

 question was taken, were either in the egg or in the first moult. A 

 (lay or two after closing the gall, I re-opened it, and the larva then 

 appeared to have increased in size ; this struck me as rather singular, 

 and my curiosity being awakened, I determined to watch its progress, 

 so it was again carefully returned to the bottle. In the course of five 

 days it had become a pupa, and more than double the size of the larva 

 when I first saw it, the pupa itself being smaller than the full-fed 

 larva. From this observation it became clear to me, that whatever 

 the larva may have been before I noticed it, it was undoubtedly, when 

 under my scrutiny, a vegetable-feeder, feeding on the juices of the 

 gall, which I had managed always to keep fresh. The following year 

 I endeavoured to repeat my observations, but without success, although 

 I examined hundreds of galls. I did notice one curious fact : in one 

 gall I found a saw-fly larva, about three-fourths fed, along with a 

 parasitic larva ; but an accident prevented my seeing the issue of this 

 case of what might be termed commensalism. 



It will be remembei-ed that Dr. Griraud (in his Memoir on the 

 Insects of the Eeed and Triticum re^jens) has detailed observations 

 clearly proving that Pimpla graminellcB is, at least partly, phyto- 

 ])hagous in the galls on the last-mentioned plant ; and the Chalcid, 

 Aulofjymnus aceris, in the galls of Bathyaspis aceris. 

 Glasgow: lith ]Sfove7)iber, 1816. 



NOTES ON THE DEGREE OF TENDENCY TO VARIATION EX- 

 HIBITED BY THE LEPIDOPTERA OF PEMBROKE AND ITS 

 NEIGHBOURHOOD. 



BY C. a. BARllETT. 



The interesting papers on variation by Mr. Birchall and 

 Dr. Buchanan White, in recent Nos. of the Magazine, have brought 

 the subject so prominently forward, that it becomes almost a duty 

 tliat those who are able to collect, in districts subject to any peculiar 

 climatal influences, should record the apparent results. 



In Pembrokeshire the climatal conditions are so peculiar, that 

 over the greater part of the southern half of the county ^ree-feeding 

 species of Lepidoptcra are almost totally absent, and the number of 

 species to be found is remarkably small. This arises, no doubt, in 

 part, from the mildness of the winters, and, in a far larger degree, 

 from their extreme humidity ; but I think that the principal cause of 



