THE CA.NADIAN ENTOMOLOGIST. 235 



NOTES ON THE STRIDULATION AND HABITS OF 

 RANATRA FUSCA, PAL. B. 



BY J. R. DE LA TORRE BUENO, NEW YORK. 



Little is known regarding the sounds produced by the Rhynchota, 

 and that little refers almost exclusively to the Cryptocerata, of which 

 Corixa has had the most attention ; and some few observations have been 

 made on Nepa, Sigara and Notonecta. It seems to me, therefore, that it 

 would be well to put on record the observations and notes made by me on 

 the striduiation of Ranatra., together with a few other remarks on this 

 insect. 



Ranatra fusca, Pal. B., supposed to be the common form in the 

 north-eastern portion of America, on being removed from its natural 

 element, gives forth a peculiar note. Recently I have had the opportunity 

 to study this at close range, in a specimen at present living in my 

 aquarium. On taking the Hemipteron out of the water, the striduiation 

 can be plainly felt by the fingers, even though, as is at times the case, no 

 sound is audible. The vibrations, when heard, produce a rasping, creaky 

 chirp. Careful examination shows that the sound-producing apparatus of 

 Ranatra departs somewhat from the more commonly met devices, while 

 being similar to that in other insects in regard to the general method of 

 producing tonal vibrations by the friction of suitably roughened surfaces 

 in contact. The stridulatory areas in this insect are situated in the deep 

 and elongated coxal cavities of the first pair of legs. This, as far as I 

 have been able to learn, is an unusual position, which is not mentioned by 

 Packard in his "Text-book of Entomology "; nor have I been able to find 

 any reference to the production of sounds by Ranatra in the literature on 

 the subject that I have been able to consult. 



For the proper comprehension of the modus operandi, a brief and 

 necessarily superficial description of that portion of the thorax in which 

 thecoxfe are set is not out of place. The narrow, elongated prothorax of 

 Ranatra is not of sufficient widtli to receive both coxte with any space 

 between them. In order, therefore, to provide for this, the segment in 

 question expands cephalad, and is provided with two deep slits extending 

 to the anterior margin, one on each side, for the reception of the coxse. 

 Due to the extreme shortness and transverseness of the head, 'the lateral 

 processes of the cavities have the appearance of cheeks, and resemble 

 somewhat the cheek-pieces of a Greek helmet. The coxre rub against the 

 inner surface of the exterior walls of the cavities. Doubtless this surface 



