36 



supposed the failure was in my power of demonstrating them rather 

 than in their being really absent. 



The presence of these bristles is hardly if at all noticed by our 

 authorities* on these structures, and they are sometimes difficult to 

 observe ; they are hidden amongst the scales, and the removal of the 

 scales often means the removal of the bristles also. The bristles do, 

 however, sometimes remain after the removal of the scales, having 

 apparently a firmer attachment. I find the best way to demonstrate 

 them is to decolorise the wing and mount it transparently ; the 

 scales then become hardly visible, whilst the bristles retain enough 

 brown chitinous colouring to be observable. In the more delicate 

 structures of the minuter moths it is obvious that it must be diffi- 

 cult to sufficiently assault the scales without damaging also the 

 bristles. 



The Nocture perhaps display these marginal bristles as well as 

 any family, but they are present in all the other families of larger 

 moths, and I am inclined to say in all species. 



The bristles along the nervures are less universally present ; at 

 least I have failed to detect them in many species. 



In Hepialus they appear to be absent in some species ; when 

 present they are almost typical bristles, but some slight modification 

 of their attachment appears. 



In Cossus they are very typical, though sparse ; in Z. pyrina they 

 are more numerous and as free from scale characters as in Microp- 

 teryx. I was somewhat surprised to find that in Acherontia atropos 

 they occur with hardly any modification. In Vanessa {Jo, urtictE) 

 they have rather more scale-like attachments, and their bases are 

 longer and more tapering, but in all other respects they remain 

 bristles. 



In Anthrocera transalpiiia they are very bristlelike, but in 

 A. minos they have progressed a considerable way towards being 

 scales ; their attachments differ, but only a little from those of the 

 scales : they are a little swollen at about a third from their origin, 

 and look as if striation was even indicated. 



The point, then, to which I wish to direct your notice about these 

 bristles is simply this, that we have throughout the Lepidoptera a 

 persistence, with very little modification, of the bristles that exist 

 along the nervures and margins of the wings of Hemerobiidcc and 

 other Neiiroptera and other earlier insects. That these bristles are 

 distinct from the scales phylogenetically, and though they have 

 slightly submitted to the strong tendency of all cutaneous structures 

 in the Lepidoptera to become scales, they have much more largely 

 resisted it, even in some of the highest Lepidoptera. 



* They are referred to as occurring in the gipsy moth in the report on that 

 insect by Forbush and Fernald, 1896, and as this is going through the press 

 are called attention to by Mr. Ambrose Quail in the "Entomologist" for 

 February, 1901. 



