x WATER-BOATMEN 359 



Notonecta is said to make a noise like the word chew 

 repeated three times running. The Insect at such 

 times rubs its fore-legs together. 1 



Bruyant has lately described a similar music exe- 

 cuted by the very minute Sigara minutissima. 2 This 

 little Water-boatman occurs among Myriophyllum 

 and Ceratophyllum in the lake of Chauvet (Auvergne)' 

 and has also been found in the freshwater sponge. 

 Though only a millimetre (^ in.) long it makes a 

 very distinct stridulation, and the characteristic sound 

 led to the discovery of the Insect in a new site. The 

 middle and hind legs are adapted for swimming. 

 The fore-legs are very short, and end in a single- 

 jointed tarsus, which is armed with stiff hairs. These 

 play upon the rostrum and make a noise like that of 

 a comb rubbed along a sharp edge. 



Sigara is not the only aquatic Insect which inhabits 

 the freshwater sponge. The larva of Sisyra, a 

 Neuropterous Insect, is very frequently found in the 

 larger pores. A Caddis-worm (Leptocerus) burrows 

 in the substance of the sponge, and in summer an 

 undetermined Dipterous larva is occasionally met 

 with in the same situation. 3 



The process of egg-laying by Notonecta has been 

 studied by Regimbart. 4 The Insect attaches itself 

 firmly by its fore and middle legs to a submerged 

 stalk, buries its rostrum in the plant, as if to gain 

 additional support, and makes an incision uith the 



1 P. Rcdfern, in Brit. Assoc. Report, 1859. Sections, p. 173. 



2 Comptes rendus, 1894. 



3 Weltner, in Tier- tend Pflansenwelt des Siisivassers, 



4 Ann, Soc. Entom. France, 1874, p. 204. 



