2 Is Vanessa Polychloros 



tone than is usual, sufficiently so to attract special notice. 

 The imago is rather below the average measure of Poly- 

 chloros in expanse of wings, being about the usual size of 

 UrticcB (two inches). The insect is the only individual of the 

 brood known to have varied, even in the slightest degree. 

 Although I did not see every member of the brood, I can 

 vouch for at least forty or fifty specimens, which I examined 

 carefully, and found not a trace of variation in any single 

 case. No larvae of any other species of Vaiiessida were reared 

 contemporaneously with the brood. 



I have examined the antennae of this specimen under the 

 microscope, and find that they present the special characters 

 found in Polychloros. 



From these facts I make four deductions, all of which turn 

 upon points of interest. It is from such instances of diver- 

 gence as the present that we are enabled to gain some clue 

 respecting the affinity of species known to be closely related, 

 and for this reason I offer the following observations : — 



1. As Polychloros lives upon elm and other trees, and 

 UrticcB upon nettle and low plants, the instance is valuable as 

 affording further evidence of the fact that neither a par- 

 ticular food nor a change in diet affects in any way the 

 colouring and markings of the perfect insect, so as to offer 

 jyer se & means of originating "varieties." This conclusion 

 is valid whether the specimen under consideration be really a 

 Polychloros or Urticce. Many experiments upon different 

 species of insects agree, I believe without exception, in so 

 deciding this question. 



2. On the supposition that the specimen is the product of 

 Polychloros parents, it is easy to infer either that the ovum 

 was dropped whilst the female was on the wing, or else that 

 the young caterpillar fell from a neighbouring tree soon after 

 emergence from the egg ; in either case the accident must 

 have occurred immediately over the VrticcB web. As the 

 broods of the two species rarely api^ear synchronously, the 

 conjecture is scarcely to be entertained, even if the accident 

 were probable. On such a supposition, however, it is to be 

 deduced that (if Polychloros) the society of an allied species 



