12 THE CANADIAN ENTOMOLOGIST. 



N©TES ON HYDROMETRA MARTINI, KIRK. (=;tINEATA, 



.; ,. SAY). 



, . BY J. R. DE LA TORRE BUENO, NEW YORI<U 



Genus Hydrometra, Latreille et auctt. ( = Limna6ates, Burmeisttr 

 et auctt.) H. Martini, Kirkaldy, igco ( = line|m, Say, 1832.) 



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

 Science, for discarding each other's generic and sj^cific names has in this 

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

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

 strtder. It is given more in detail in The E,B'tomologist (London, Eng.) 

 for June, 1900, on page 176, in which Kirl^aldy elucidates it, relegating 

 Saj^'s specific name to synonymy, as it unfojftunately has been preoccupied 

 by-Eschscholtz, who in 1822 described liydrometra iineata from Manila, 

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

 discusses the generic synonymy. ^ 



In March, 1900, pp. 7o-76cf The Canadian Entomologist 

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

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

 The notes I now present are lar|;ely supplementary and confirmatory of 

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

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

 in a marshy pond, we {onnd f Hydrometra Martini by the hundred. We 

 took them until we got tire^d. Again in May of this year, we took very 

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

 there, in ones and i\\os,hx 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^^ut of the water. One's shadow 

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

 ])laces, and these seemingly tiny twigs caii" 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 

 away. 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 form of 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 twg fully winged males. 



January, lyo.v 



