12 THE CANADIAN ENTOMOLOGIST. 



NOTES ON HYDROMETRA MARTINI, KIRK. ( = LINEATA, 



SAY). 



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



Genus Hydrometra, Latreille et aiictt. ( = Llmnobales, Burmeistcr 

 et auctt.) H. Martini, Kirkaldy, 1900 ( = lineata, Say, 1832.) 



The peculiar facility of the older entomologists, the fathers of the 

 Science, for discarding each other's generic and specific names has in this 

 instance, as in many others, given rise to a complicated synonymy, of 

 which I give above that covering this extremely interesting little water- 

 strider. It is given more in detail in The Entomologist (London, Eng.) 

 for June, 1900, on page 176, in which Kirkaldy elucidates it, relegating 

 Say's specific name to synonymy, as it unfortunately has been preoccupied 

 by Eschscholtz, who in 1822 described Hydrometra lineata from Manila, 

 Philippine Islands. In the paper mentioned hereafter, Mr. J. O. Martin 

 discusses the generic synonymy. 



In March, 1900, pp. 70-76, The Canadian Entomologist 

 published "A Study of Hydrometra lineata," by the last named author, a 

 most interesting paper on the habits and peculiarities of this Hemipteron. 

 The notes I now present are largely supplementary and confirmatory of 

 his work, although I may say that my labours were not directed to that 

 end. In May of 1903, Mr. W. T. Davis, took me to Staten Island, where, 

 in a marshy pond, we found Hydrometra Martini by the hundred. We 

 took them until we got tired. Again in May of this year, we took very 

 many more at the same place. Subsequently, I have found them here and 

 there, in ones and twos, or in greater numbers, without any effort, which 

 bears out Mr. Martin's experience, although I have nowhere found them 

 as abundant as at Staten Island. This little bug prefers to hug the shore, 

 hiding among the grass-stems growing out of the water. One's shadow 

 falling on it seems to disturb them, and they emerge from their hiding 

 places, and these seemingly tiny twigs can be seen moving briskly away, 

 borne on their hair-like legs, with which they run on the surface, or else 

 they remain motionless, letting some friendly little breeze waft them 



aw.iy. It is to be noticed that Hydrometra walks on the surface of the 

 water and does not propel itself by a rowing motion, as do the Gerridae 

 and other Water-striders. Its tarsi also are provided with claws terminal 

 and not set above the tip of the last tarsal joint as in the latter family. 

 The winged t'orm ©t Hydrometra Martini must be very rare in the north, 

 as out of about two or three hundred individuals I have seen, I have 

 found only two fully winged males. 



J.inuary, igo^. 



