310 ENTOMOLOGICAL SOCIETY 



in this genus projects or is raised at its free end noticeably from the 

 general surface of the body. In other saw-flies and in Uroceridas the 

 scale is applied rather closely to the edges of this opening, and in 

 Cimbexand other species fits into a depression so that careful dissec 

 tion is necessary to show its true character. This scale is usually 

 oval, but in Lyda (and less so in Uroceridse) is more or less triangu 

 lar. It is lighter colored than the rest of the body (less so in Uroceri- 

 das and some species of Lyda), is nearly transparent, and is, so 

 far as studied, hexagonally sculptured over its entire surface. It 

 is much thinner than the chitinous wall of the body and generally 

 membraneous. Beneath it is a large open space closed in whole 

 or in part by a muscular band. As I have asked Mr. Marlatt to 

 follow up the subject so far as the Hymenoptera are concerned, 

 and to give us the results at some future meeting, I will not enter 

 into further details in reference to that Order. I will simply add 

 that in the Lepidoptera, in which I have examined the types df a 

 good many families, the similarly placed but superficial spots are not 

 specialized, but are mere inflations or modifications of the chitine 

 wall. They are wanting in the Rhopalocera and in the higher 

 groups of the Heterocera, while in the Tortricina and Tineina, 

 in which they are usually well developed, they have remained 

 unnoticed for the reasons stated above. They are, in fact, struc 

 turally quite distinct from the true cenchri of the Hymenoptera 

 and recall them chiefly because of their similar position on the 

 metathorax. Yet it is difficult to overcome the conclusion that 

 the true cenchri of the Hymenoptera are, in some way, modifica 

 tions of these simple structures in the Lepidoptera. The pecu 

 liar opalescence which they often show in the Lepidoptera is 

 caused by the refraction of the light due to thickly placed chitinous 

 papillas, but so far as I have been able to see there is no modifica 

 tion of the chitine wall and no opening. 



3. THE TEGUL^E AND THE PATAGIA. 



In denuding these different species of Lepidoptera of various 

 families I was interested in noting the remarkable variation, and 

 at times the great prominence, of the tegulse, organs which are 

 usually clothed with special hairs which form the shoulder lap 

 pets, and the actual chitinous structure of which is generally 

 overlooked by lepidopterists. I exhibit certain specimens to 

 show how these tegulae when denuded form prominent tubercu 

 lous or scale-like projections, and are the more conspicuous by 

 virtue of the different coloration from the rest of the thorax. The 

 strangest thing about them, however, is that they have been con 

 founded by most authors with the patagia. On the authority of 

 Westwood (Vol. II, page 314) Kirby and Spence were the first to 

 definitely point out and describe the appendages of the prothorax, 



