NO. 9 OLFACTORY SENSK OF INSECTS McINDOO 15 



and by cuttini^' them off at the base the sense of smell is totally or par- 

 tially destroyed; (2) covering the antennae with a layer of india 

 rubber renders these organs insensitive; (3) sometimes a little sensi- 

 bility is shown when the palpi are amputated. Thus in the articulates 

 the organs of smell reside in the antennae and in the palpi, but the 

 antenucc recognize odors from afar and from near by, while the palpi 

 recognize only distant odors. In the plumose, flabellate or pectinate 

 antenucX olfactory organs are present in all the branched parts. In 

 the simple and setaceous pr filiform antennae the organs of smell are 

 principally in the last joints and diminish toward the base. In 

 antenme terminated with a club the organs of smell are exclusively 

 in the club. lie believes that the organs of smell are present in the 

 last joint of the palpi. 



Cornalia ( 1856) says that the manner in which insects move the 

 antennce shows that these appendages serve for searching when the 

 odor is scattered. He observed a male Bomby.v mori that was trying 

 to enter a small box in which a female was enclosed. After he had 

 cut off the antennae of this male- it approached the box with uncer- 

 tainty and sometimes did not go to the box at all. The same result 

 was obtained by covering the antenuce. His view is similar to that of 

 Perris in that the seat of olfaction lies in both the antennae and palpi. 

 Gamier ( i860) is certain that articulated animals perceive odors. 

 Bees that go foraging for a long distance quickly recognize their 

 hives without the aid of their acute vision. An organ of olfaction, 

 wherever one may observe it, is an expansion of very fine skin, abund- 

 antly supplied with vessels and nerves, and moistened with a viscid 

 fluid which permits the intimate contact of the odor. He does not 

 state where the olfactory apparatus lies in insects, but he denies that 

 the antenna performs such a function, because when the knobs of the 

 antennae or the entire antennae of individuals of the Genus Nccroph- 

 agiis were detached, the insects returned immediately to the body of 

 a mole from which they had l)een temporarily removed. 



Balbiani (1866) put unmutilated female butterflies in one box and 

 in a second box he placed males of the same species. Some of the 

 latter had their antenna cut ofl:'. As soon as the box containing the 

 females was placed under that of the males, the unmutilated males 

 moved their antenna, vibrated their wings and quickly moved their 

 legs, while the mutilated ones remained perfectly quiet. In this ex- 

 periment he says that sight and hearing were excluded and thinks 

 that olfaction brought about by the antennae is entirely responsible 

 for these responses of the males. 



