Linncean Society. 379 



between the cells, which open into follicles connected with sinuses 

 in the granular tissue of the body, and that the orifices (the spiracles) 

 at first very closely resemble the stomata of plants. The parietes of 

 these follicles in Melo'e are formed by aggregations of exceedingly 

 minute, nucleated embryo-cells of rounded shape, and about one five- 

 or one six-thousandth of an inch in diameter. 



The tegument of the head, and more especially that of the eye of 

 the young Melo'e was then examined, and the cornea, which in this 

 stage of the insect's existence is a single structure, fitted only for 

 near vision, was shown to be composed of numerous transparent der- 

 mal cells, continuous with those which form the surface of the head, 

 while the centre of the cornea, the axis of vision, is occupied by a 

 single cell, more projecting and twice the size of those which sur- 

 round it. 



The changes which take place in the relative development of dif- 

 ferent parts of the tegument of the young Melo'e, which lead to its 

 entire alteration of form, were then pointed out, and shown to occur 

 chiefly in the rapid growth of the dorsal region, which from being 

 originally the smallest, as it is the last-formed part of the body, be- 

 comes the most voluminous, and occasions a complete alteration in 

 the position and size of the limbs and in the entire form of the in- 

 sect. 



The stages of this process and the formation of the dermo-skele- 

 ton, the author proposed to be considered in the next section of this 

 memoir. * • 



Nov. 16. — The Lord Bishop of Norwich, President, in the Chair. 



E. Doubleday, Esq., F.L.S., read a paper " On the Pterology of 

 the Diurnal Lepidoptera, especially upon that of some genera of the 

 Heliconidce." 



After expressing his regret at the little attention bestowed in this 

 country upon the anatomy of the Annulosa, the writer proceeded to 

 remark that he was not aware that any author had recorded the fact 

 of a sexual variation in the neuration of the wings of Lepidoptera, a 

 fact extremely interesting from the light it throws on the homologies 

 of the nervures and nervules. 



The variation takes place in the genera Ithomia, Mechanitis and 

 Sais, all remarkable also for the great sexual variation in the struc- 

 ture of the anterior legs, those of the males being the least de- 

 veloped, those of the females the most developed, of any butterflies 

 with suspended pupse. 



The state of atrophy of the anterior feet of the males is not, he 

 states, the consequence of excessive development of the other pairs 

 of feet, or of any other organs, nor does it appear to depend on any 

 peculiar habits of the insect ; neither can the greater development 

 of these feet in the females be accounted for by any difference of 

 habits. For the more developed anterior feet of some male Coleo- 

 ptera, for the powerful jaws of the leaf-cutting or timber-boring bees, 

 there are obvious uses ; but a greater development in the one sex of 

 organs almost atrophed in the other, which still leaves them unfitted 



