OF \YATERBUGS, ESPECIALLY OF CORIXIDAE. 39 



elytra are firmly adpressecl to the abdomen to prevent the 

 ingress of water, and moreover the folded lower wings com- 

 pletely cover over the strigil in this position. For the purpose 

 of mating, these bugs often migrate to a neighbouring piece of 

 water, and it is possible that during flight some of the spines on 

 the posterior legs may be drawn across the strigil ; otherwise the 

 method of operation does not appear clear. 



It has been remarked that the purpose of stridulation is not 

 apparent, as no auditory organ has been observed in either sex, 

 especially, of course, the female. Too much stress must not be 

 laid on this, as no special auditory organs have been detected 

 even in the Cicadidae. It is probable that the rhythmic sounds 

 produced by the male Corixidae are transmitted through the 

 water and perceived by the females by means of some of 

 the numerous bristles scattered over the body. It has been 

 suggested that the convex, hollow pronotum may serve as a 

 sounding board, but there does not seem to be much in this 

 hypothesis. 



It will be evident, from a perusal of the foregoing, that 

 there is an interesting field open during the next few months for 

 observations as to the real nature and actual modus operandi of 

 the stridulation in Corixidae. 



I proceed now to briefly describe the palae, etc., of the various 

 species. 



Genus 1. Micronecta Kirkakly. 



(= Sigara in Saunders, Hemipt. Heteropt. Brit. Isl.) 



Face convex in both sexes. Strigil present in the male. No 

 sti-idular area. Palae subovate, terminated by a powerful knife- 

 shaped claw in the male, stridulator composed of bristly hairs 

 scarcely distinguishable from the other palar bristles. Palae 

 elonsrate-cultrate in the female. 



'O" 



Species 1 (Fig. 6). M. minutissima (Linne). 

 Species 2. M. scholtzi (Scholtz). 



Fig. 36 represents the strigil in M. signoreti, an African species, 

 and is copied from Handlirsch's figure. 



