examining a series of specimens he found it to be only C. Smenth- 

 manniann. In view of this last circumstance I think we must wait 

 for further evidence before admitting Graplwlitha Zebeana to a place 

 in the British list. 



39, Linden Grove, Nunhead : 

 April, 1896. 



OI^ THE STRUCTURE AND DEVELOPMEXT of the LEPIDOPTEROU.S 



WING-. 



BY D. S^IARP, M.A., F R.S., &c.' 



It has long been known that rudiments of the wings of tlie 

 butterfly can be found in the interior of the body of the caterpillar, 

 and Verson has recently stated that he has found them in the embryo 

 caterpillar some days before the young silkworm leaves the egg ; when 

 it appears that these rudiments consist of a few cells in close pro- 

 pinquity with a tracheal branch ; the position is on the interior of the 

 wall of the body on the second and third thoracic segments. By the 

 growth of the cells a projection into the interior of the body is formed, 

 the structure being essentially of the nature of an invagination or 

 inward growth of the layer of cells forming the inner part of the 

 wall of the body, and usually called the hypodermis. The growing 

 structure retains a remarkable relation with the tracheal system, and 

 as the cells increase, the tracheae multiply and assume a complex form, 

 so that branches of minute, rolled up, tracheae are found in the wing- 

 rudiments. In the course of the growth it appears there are, according 

 to Gonin's account, two separate consecutive tracheal systems. 



While the caterpillar is in search of a place in which to change 

 to a chrysalis, the wings disappear from the interior of the body, and 

 if the outer layer of the cuticle be stripped off they will be found 

 immediately under it, so that when the skin is cast off the wings are 

 visible on the exterior of the body. 



The mode in which the wings change their position has not been 

 satisfactorily made out, but Gronin considers it is chiefly due to a rapid 

 destruction of the hypodermis external to the wing, and its reconsti- 

 tution internally thereto. 



When the wing becomes an external oi'gan a rapid increase of 

 size, especially of length, occurs. The wing is not at this time, as it 

 is subsequently, a sheet-like structure, but is rather a bag filled with 

 the nutritive fluid of the body and other living matters. At the 



♦Abstract of a communication made to the Cambridge Entomological and Natural History Society. 



