Caterpillar and chrysalis, natural size; branched spine from
caterpillar, magnified.
FIG. 13.—GREAT TORTOISE-SHELL BUTTERFLY, VANESSA POLYCHLOROS, L.
July 27, 1894.
I am very much pleased to hear that you have hatched two of the Large Tortoiseshell butterflies from your specimens. This is very interesting as completing your previous observation, and I am particularly glad of this note of date of development for I am afraid that the only really good chrysalis which I secured from your larvæ does not seem likely to develop. However, it gave me an opportunity of seeing the beautiful colours and the six bright mother-of-pearl-like spots on the back. Many thanks for kindly offering me a specimen, but I should not like to take it—for it is of special interest with you to illustrate this rare attack, and also it is very difficult to ensure safety in transmission. Many thanks all the same, and also for your Hessian fly specimens received a short time ago, and for the further notes now. I am sorry not to have acknowledged them and the information in the letter accompanying them sooner, but I had a deal of work, and some temporary difficulty from breaking a blood-vessel in one eye. However I am thankful to say that is all right again.
I have no doubt you are right about the weather making a most important amount of difference in extent of injury both from Hessian fly and Diamond-back attack. If it had been hot I am afraid Plutella cruciferarum (Diamond-back moth) would have done a deal of mischief. The little Charlock weevil, Ceuthorhyncus contractus (see my seventeenth, 1890, report), has been doing a great deal of mischief to young turnips at some places on the east side of the country.
In usual position, and also with wings expanded—magnified; also natural size.
FIG. 14.—CHARLOCK WEEVIL, CEUTHORHYNCUS CONTRACTUS.
July 30, 1894.
The V. polychloros specimen came to hand little, if at all, injured by its journey, and in beautiful order for figuring. I am very glad to have it, for besides proving the caterpillars to be of the “great tortoiseshell,” I had the opportunity of seeing the row of long bristles or stout hairs about a third along the lower part of the front edge (the costa) of the fore-wings. This row of hairs is the structural difference between this “great tortoiseshell,” and the “small tortoiseshell” (which is without them), but otherwise the two species are so much alike that there used to be doubts whether they were not merely varieties until this point was noticed by a Dutch entomologist, Mr. Snellen. I shall be glad to refer to this point, for it is important and was observed after our chief manuals of Lepidoptera were published.
On referring to your letter accompanying the Hessian fly puparia, “flax-seeds,” in which you notice some of them being within the stalks, I remembered I had not precisely replied to this part, so I do it now. I think this position, though not characteristic, is not very uncommon, and is caused by a weakness of the stem. I have from time to time found the stem cracked longitudinally and the “flax-seed” partly slipped into the cavity.
