1892.] MR. A. Thomson's report on the insect-house. 193 



experience. I found the structure to be present in Ageronia 

 feronia and arethusa. 



The other structure to which I wish to draw attention is the dis- 

 tortion of the hind wing found in the males of certain Noctuina of 

 the subfamily Ommatophorince, e. g. Patula macrops and the various 

 species of the genusArgiva, large Moths very common all through the 

 East. In the females of both Patida and Argiva (fig. 4) the neuration 

 is of the ordinary Noctuid character. In the males of Patula (fig. 5) 

 there is a very large glandular fold covered with long, silky, closely 

 matted hairs, and with a tuft of long hairs projecting from it,' attached 

 to the costa and folded over on the upper surface of the wing, and 

 one notices that instead of the usual nine emarginatious of the outer 

 margin there are only five. But it is not till the wing is denuded of 

 scales that we see the nature of the change that has taken place; 

 when this is done, we see that instead of vein 8 going to the apex 

 of the wing it is vein 4 that does so, that the functional apex 

 is really the middle of the outer margin, and that the whole costal 

 half of the wing has been transformed into the glandular fold, 

 carrying the nervures with it, perhaps for purposes of nutrition. 



In the males of Ar(/iva(Gg. 6) we find that this has gone one step 

 further ; the fold and glandular patch are very small, but it is vein 3 

 that goes to the apex and there are only four emarginatious of the 

 outer margin, the other veins being represented by small aborted 

 detached fragments near the base. 



The glandular fold is almost certainly a scent-organ, and I suggest 

 that Argiva once possessed an even larger one than Patula, and 

 that this fold, becoming detrimental or useless to it, either from 

 hindering flight or some other cause, has been aborted, carrying the 

 neuration with it. 



March 1.5, 1892. 



Prof. Flower, C.B., LL.D., F.R.S., President, in the Chair. 



Mr. Arthur Thomson, the Society's Head Keeper, exhibited a 

 series of Insects reared in the Insect-house in the Society's Gardens 

 during the past year, and read the following Report on the subject : — 



Report on the Insect-house for 1891. 



Examples of the following species of Insects have been exhibited 

 in the Insect-house during the past season : — 



Silk-producing Bombyces and their Allies. 



Indian. 



Attacus atlas. Anthercea mylitta. 



cynthia. Actias selene. 



pernyi. Cricula trifenestra. 



