190 OUR HOUSEHOLD INSECTS 



minute joints, followed by a long tapering bristle, from 

 the sides of which project other similar but smaller hairs. 

 This style of antenna, viz., three joints and a terminal 

 bristle, is the usual type amongst a large section of the 

 order Diptera, which, from the shortness of the organ, 

 are called Brachycera (short-horns), the other division, 

 Nemocera (thread-horns), containing only the gnats, 

 mosquitoes, daddy long-legs, &c., in which the antennae 

 are of the ordinary tapering, hair-like type. In the 

 bluebottle, the terminal joint of the antennas is excep- 

 tionally large, and is probably connected with the 

 wonderful acuteness of the sense of smell which dis- 

 tinguishes the species. Its whole surface is crowded 

 with tiny hairs, and between these the skin is covered 

 with enormous numbers of extremely minute clear dots, 

 some 17,000 or 18,000 having been estimated by Lowne 

 as the number for each antenna. Scattered amongst 

 these are also a few larger ones of a similar character : 

 they are minute pits, the larger of which at least are in 

 communication with nerve-threads. 



That antennae may be organs of smell seems to be 

 indicated by experiments on the part of several observers. 

 Take, for example, one of Sir John Lubbock's. Speaking 

 of an ant which had been tethered to a board, he says, 

 " I approached the feather of a pen very quietly, so as 

 almost to touch first one and then the other of the 

 antennae, which, however, did not move. I then dipped 

 the pen in essence of musk, and did the same; the 

 antenna was slowly retracted and drawn quite back. 

 I then repeated the same with the other antenna. If 

 I touched the antenna, the ant started away, appa- 

 rently smarting. I repeated the same with essence of 

 lemon and with a second ant. The result was the 

 same." Now, when we remember the annoying cleverness 



