ANTENN.E OF LEPJDOrXERA. 17 



nary sounds which ure sensible to our ears. It does not follow, how- 

 ever, that they do not hear sounds of which we are not cognizant. 

 Dr. H. Landois* gives an account of sound-producing organs among 

 insects and describes sounds produced by eleven species of Lepidop- 

 tera with which he experimented. In many cases the sounds were 

 weak, but he says the weakness. of the tones of many was due partly 

 to the lightness of the sound, partly also to its being of such a nature 

 that it cannot be perceived by human ears. The senses of touch 

 and hearing are doubtless very intimately connected. That the an- 

 tenna! hairs of certain Diptera are auditory organs has been pretty 

 clearly demonstrated, and it is not at all improbable that the an- 

 teunal hairs of the Lepidoptera may be of some use for the detection 

 of sound. The set of apparatus described under section (5 seems 

 especially adapted to the perception of any sort of delicate pulsa- 

 tions of sound waves. C. M. Childf has described this apparatus, 

 which he terms " Johnston's Organ," as found in the Culicidte and 

 Chironomidre, where it has a remarkable development. He believes 

 that its functions as an organ for the perception of both touch and 

 sound, and that the insect is able to distinguish between the two 

 sensations by whether any resistance is offered to the free movement 

 of the antenna. 



EVOLUTION OF THE ANTENNA. 



In the preceding chapter I have described the general form and 

 structure of the antennas of the Lepidoptera. I have also endeavored 

 to indicate the character of the organs found upon them and to ai-- 

 rive at some conclusions regarding their function. In the present 

 chapter I shall point out what I believe to l)e the primitive form of 

 Lepidopterous antenna, and to indicate in a ])artial manner the 

 paths by which the evolution of the more specialized forms has taken 

 place. 



The most generalized form of antenna of existing Lepidoptera so 

 far as I have been able to examine specimens is to be found in the 

 genus Mloroptenjx. The genus contains two distinct types, but M. 

 semipurpurella may stand as the representative of the one which 



"•■■" Die Ton- und Stimin-apparate der Insekten in anatoiuisch-physiologischefl 

 und akustis<-lieu Bezieliung. Zeit. f. w. Zool. Bd. 17, pp. 105-186. 



t Eiii bislier weuig beaclitete antennales Sinnesorgan der Insekten, niit besonder 

 Berucksichtigiing der Culieiden und Chirouononiideu. Zeit. f. w. Zool. Bd. 38, 

 1894. pp. 475-528. 



TRANS. AM. Kx\T. SOC. XXIII. (3) JANU.\RY, 1896. 



