30 i-i"iy. 



the accompanying figure of nymph and imago, appears to be Naucoris 

 cimicoides, Lin.), produces, with its neck, a noise like that made by 



the Longicorn beetles (Beschr. 

 YOU. all. Ins. in Deutsch., 1766); 

 I dubiously experimented on 

 some specimens of iV. cimicoides, 

 and, finding a faint sound like 

 that produced by the scratching 



a 



a. Mesothorax of JWiMcom cimicoides, front view, n m •, iij.j_- 



I. L limaj. 01 a needle point would at times 



ensue when the overlap of the delicate, yet tense, pronotum, was moved 

 to and fro, and slightly pressed on the mesonotum, I was led to examine 

 the lateral front angles of the latter, where I detected a minute 

 y^shaped lima, thickly set with striae, the limae being more distinct in 

 the male. 



I next investigated a specimen of the water scorpion, N'epa cinerea, 

 Lin. (very kindly sent me, with some other named Hemiptera, by 

 Mr. Douglas), and finding the edge of the pronotum, if depressed and 

 worked over the mesonotum, elicited a still sharper click or crackle, I 

 proceeded to inspect the superior lateral angles of the latter, and dis- 

 covered there two triangular, convex, striated surfaces, resembling, in 

 all respects but position, the limse of many Longicorn beetles, although, 

 as in all the Hemiptera I have chanced to examine, desiccation had 

 somewhat impaired their symmetry and potency. 



In Corixa Panzcri, Fieb., the limae are again seen,y-shaped and 

 elongate ; and the sinuated sides of the sub-triangularly produced 

 pronotum appear faintly dej)ressed, so as to work over them. One of 

 this genus, Corixa striata, Curt., it will be seen, by referring to the 

 Report of the British Association for the Advancement of Science for 

 1845, pp. 64, 65 (1846), has been recorded as a stridulator. " Mr. Ball 

 noticed the fact of one of the Notonecfidce {Corixa striata, Curt.) 

 emitting loud and powerful sounds, somewhat like those of a cricket. 

 These sounds were given out while the animal was about two inches 

 and a half under water, and so loud as to be distinctly audible in an 

 adjoining room through the closed door. The first observation of this 

 fact was made about two years since, by Miss M. Ball, who has since 

 frequently verified the original observation. Mr. Ball stated that he 

 had himself heard, on the 15th June, this remarkable sound. It is 

 probable the sound is only emitted by the male : it has, as yet, only 

 been heard in the months of May and June." 



Lastly, I have examined a specimen of Notonecta glanca, Lin., 



