SEXUAL SELECTION 



373 



at the entrance of his burrow, and stridulate until a female 

 approaches, when the louder 

 notes are succeeded by a more 

 subdued tone, while the suc- 

 cessful musician caresses with 

 his antennae the mate he has 

 won. ' ' " Dr. Scudder was able 

 to excite one of these insects 

 to answer him, by rubbing on 

 a file with a quill." In both 

 sexes a remarkable auditory 

 apparatus has been discovered 

 by Von Siebold, situated in 

 the front legs." 



Fia. 11.— Gryllus campestris (trona Lan- 

 dois). Bight-hand figure, under side of 

 part of a wing nervure, much magnified, 

 showing the teeth, st. Left-hand figure, 

 In the three Families the upper surface of wing-oover, with the 



projeotmg, smooth nervure, r, across 

 sounds are differently pro- '^^^'^'^ t^e teeth (s<) are scraped. 



" wing-covers 



field- cricket 



are differently pro- 

 duced. In the males of the Achetidse both 

 have the same apparatus; and this in the 

 {Gryllus campestris, Fig. 11) consists, as de- 

 scribed by Landois, " of from 131 to 138 sharp, 

 transverse ridges or teeth (st) on the under side 

 of one of the nervures of the wing-oover. This 

 toothed nervure is rapidly scrape"d across a 

 projecting, smooth, hard nervure (r) on the 

 upper surface of the opposite wing. First one 

 wing is rubbed over the other, and then the ^^^ 12 -Teeth of 

 movement is reversed. Both wings are raised nerrure of Gryiius 



o domesticus (from 



a little at the same time, so as to increase the Landois). 

 resonanc;e. In some species the wing-covers of the males 

 are furnished at the base with a talc- like plate.'' I here 

 give a drawing (Fig. 12) of the teeth on the under side 



" "The Naturalist on the AmazonB," vol. 1., 1863, p. 252. Mr. Bates gives 

 a very interesting discussion, on the gradations in the musical apparatus of the 

 three families. See also Westwood, "Mod. Class.," vol. ii. pp. 445, 453. 



32 "Proc. Boston Soc. of Nat. Hist.," vol. xi., April, 1868. 



33 "Nouveau Manuel d'Anat. Comp.," French translat., torn, i., 1850, 

 p. 5S1. 



3< "Zeitschrift fiir Wissenschaft. Zoolog.," B. xvii., 1861, s. 117. 

 2' Westwood, "Modern Class, of Insects," vol. i. p. 440. 



