MosLEY : On Causes producing Variety in Lepidoptera. 67 



approach C. Eebe, and an Ado7iis in Mr. Weston's cabinet is shot with 

 copper on the under side of the same colour as that on the upper side 

 of P. pfilceas. Argynnis Euphrosyne seems to have a tendency to 

 become black at the base of the wings, and in this respect approaching 

 to A. Frieja^ Thunb., and many other cases could be cited where one 

 insect seems to approach the form of another, and generally one that 

 bears some close relationship to it. 



There is another variation to which some insects seem particularly 

 liable, to which I have not yet called attention, and that is the 

 bleached appearance frequently seen in 8atyrus Janira^ often in the 

 form of round spots, and often corresponding on the two sides. I 

 have seen what appears to have been brought about by a similar 

 cause in S. Tithonus, F. piniaria, S, ^geria, and I think also in Erehia 

 Blandim. I also know of three specimens of Chelonia caja, (Sydney 

 Webb, C. S. Gregson, and F. Bond) in which the brown on the upper 

 wings is nearly bleached away, the red on the lower wings changed 

 to a pink, and the usual black spots a pale drab. One underwing of 

 a male ;S^. carpini in the late Mr. Owen's collection is the same, and 

 such thing occurs also in the burnets. In the case of Janira, Mr. 

 Gregson suggested that it might be caused by an old bottle or a dew- 

 drop focussing the rays of light upon the pupae, which in this species 

 are exposed ; and this idea seems strengthened when he told m.e that 

 such Caja as the ones referred to above could be produced by the 

 pupse being long exposed to the sun. In the case of greenhouse 

 plants, too, we frequently find that camellias, &c., are often scorched 

 and discoloured by a speck in the glass focussing the rays strongly on 

 one particular leaf, and the gardener has to put a dab of paint over 

 the speck to stop the rays. After emergence, too strong light 

 destroys some colours in lepidoptera, and for some time I thought 

 that this was the true explanation of the bleached appearance in 

 Janira. But if the spots were caused by focussing of the light, it 

 would only touch on one part of the pupa, and could not be thrown 

 on two sides corresponding exactly as they frequently do. It seems 

 to me, in tliis case, that the bleaching more probably is caused by 

 fluid touching the two wings when they are hanging to dry. In the 

 case of F. piniaria the bleaching is confined to one side, and in all 

 cases except Janira to the margin of the wings. 



It is noteworthy that in lepidoptera we never find an albino. In 

 the vertebrate animals, and especially in the birds, albinos are of 

 frequent occurrence ; in fact birds do vary generally in colour, 

 seldom in position of marking. But in all the hundreds of varieties of 



