36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



Packard believes that this structure is an olfactory apparatus. He 

 calls this a " simple nose," while in the caudal styles of the cockroach 

 there is a " compound nose." 



ORGANS ON BASES OF WINGS AND ON LEGS AS OLFACTORY 



ORGANS 



While examining the organs on the halteres of flies, Hicks (1857) 

 discovered on the bases of the wings peculiar structures which he 

 called vesicles, arranged in a single row extending some little distance 

 up the vein on both sides of the wing, but principally on the upper 

 side. By examining insects of other orders he ascertained that 

 these organs are not confined to the Diptera. He believes that they 

 are found in all insects, and they were present in all specimens ex- 

 amined by him. They exist on both sides of the wing, but chiefly on 

 the upper side of the base on the subcostal vein and in the Hemiptera 

 on the costal vein. Those on the hind wing are generally larger in 

 size and greater in number. 



In Moths they are very apparent, being greatest in the Noctuae [Noctuidae] 

 and Bombycidae. There are about 100 vesicles on the upper surface of the 

 posterior wing, and half that number beneath, besides some few on the 

 nervures [veins]. In the butterfly they are smaller, but arranged in more 

 definite groups, about three in number. In Coleoptera and Neuroptera they 

 are arranged in long rows along the subcostal nerve ; they are more apparent 

 in Coleoptera than in Neuroptera. In the Hymenoptera, for instance the bee, 

 they are found in a rounded group of about forty on each side. 



Are they organs of smell, as suggested by Mr. Purkiss? As the olfactory 

 organ has never yet been decided on, it seems to me not improbable that they 

 be the organs of that sense; for, first, it is not likely that they should be the 

 organ of hearing, as they are in constant motion, and situated near the source 

 of the hum of the wings, so that other sounds would be drowned, 2ndly, it is 

 not necessary that the power of smell should be in the head. It is situated in 

 the commencement of the air passages in the upper animals probably because 

 the current of air or water passing the olfactory nerves is there most powerful ; 

 but in the spiracle-breathing insects the greatest currents are in the neighbor- 

 hood of the wing, and near the greatest thoracic spiracle. The motion of the 

 halteres also permits a greater exposure to odors floating in the air. 



He claims that the organs on the halteres and on the base of the 

 wings are similar in structure and probably have the same function, 

 that of smell. He was able to trace a nerve to each group of organs, 

 the one going to the hind wing being the larger. 



Hicks (1859a) presented a second paper concerning these organs 

 in which he asserts : 



I may here repeat that each of these structures consists of very thin and 

 transparent,- hemispherical or more nearly spherical projections from the 



