31 



On some Wing Structures in Lepidoptera. 



By T. A. Chapman, M.D. Read December \ph, 1900. 



The wing structure of Lepidoptera is a very wide subject, with a 

 very considerable literature, which I propose to touch at only a few 

 points, chiefly because they are some that have interested me and 

 may perchance have some interest for you. I have selected a few 

 items on which 1 can report to you entirely from my own observa- 

 tions ; not by any means that I have more than an odd point or 

 two perhaps that is at all novel. Still those that are not new may 

 be none the worse for being presented as a result of observations 

 that confirm or modify well-known conclusions. I have avoided as 

 far as possible matters that are treated in British text-books, or 

 which you may have found expounded more intelligibly than I can 

 pretend to in some of our magazines. 



In discussing the Lepidopterous wing from any aspect it is always 

 an assistance to first consider that aspect in those families that are 

 most nearly related to the probable earliest Lepidopteron or its im- 

 mediate ancestor. If we examine a wing of almost any Neuropteron 

 of the family HeinerolnidiC, or better of the Fanorpidct; as probably 

 still nearer to the Lepidoptera, we find it possesses two forms of 

 clothing. 



The wing is clothed all over by a number of fine points, often 

 prolonged into minute hairs. A careful examination of them, 

 however, shows them not to be what we usually understand by hairs 

 in insects, viz. a tapering, usually hollow process attached to its 

 base by a joint, that permits its being moved to different angles with 

 the surface. These are, on the contrary, processes of the surface of 

 the wing itself, without joints and permanently fixed in one attitude. 

 The other form of clothing consists of true hairs or bristles. There 

 are no scales or hair-scales. 



Let us discuss, in the first place, the small spicules that clothe the 

 wings entirely in Panorpa. My attention was first called to these 

 by a paper by Professor Kellogg, that appeared in the Kansas 

 "University Quarterly " for July, 1894, and later in the "American 

 Naturalist." The central matter of that paper was the existence of 

 these spicules on the wings of the Jugataj of Comstock, and their 

 non-existence on the wings of other Lepidoptera, showing the much 

 closer relation of the Jugate to the Neiiroplera than of other 

 Lepidoptera, which is correct ; and adding another character by 

 which they may be distinguished from other Lepidoptera. The 

 latter idea, however, does not accord with the facts on further 

 research. On examining the matter I met with other Lepidoptera 

 that possessed them, all belonging to the family Adelida, which I 

 always have believed to be very directly derived from the Erie- 



