BTTLLETIN OF THE UNITED STATES I'TSTf COMMISSION. .'553 



Vol. VI, ]Vo. 23. W»<!;hiiis:to6i, «. C. Dec. 31, 1886. 



lOn.-KRr.Oi^TOITlin^ AlVn SOITIE OTIYER FlIs^II-nKSTROVIIVO BU«8. 



Ky 0E0R€;E DIITI]TI0€K. 



[From Animal Ivppmt nl' llic V\s]\ and (iaiiie Commissioners of Masaacliiisctts, lH8('i. ] 



Insects are oenerall.v (considered to be beneficial to fishes by iiirnisli- 

 \v.g them one of the most unfailing sources of food. There are, however, 

 a few insects which are injurious to fishes, thus makings an exception 

 to the rule. DeGeer' i)ul)lished a statement in ITT't that the larvjB of 

 drajjon-fiies, or, as tliey are vsometimes called, devil's-darning-ueedles 

 (the JAheUulUla', of naturalists), would seize and kill fishes, a statement 

 (joidirnied by Dale^ in 1832. Von IMuetzschefahl' in 1778-'70 mentioned 

 several aquiitic insects which attacked the perch, among them two 

 species of water-beetles {Dytiscidw) and two species of wa.ter-bugs 

 {Notonecfa (jlauca, aiul Nepa linearis — now called Ranatra linearis). 

 The destruction of young fishes by water-beetles lias since beeu uoted 

 by Elles* in 1830, by Dale'^ in 1832, and by Eiley'' in 1885. In regard 

 to the water-bugs, observations published within the past few years 

 have not only confirmed the above-mentioned earlier statements, but 

 other bugs have been discovered to attack fishes. Leidy,''' as early as 

 1847, writes that species of Belostoma and Perthostoma {Zaitha) prey 

 upon fishes. Glover," in 1875, states that Ranatra quadridenticulata 

 aiul Belostoma americamim feed on small fishes, and that N'epa apicuJala 

 probably, and Notoneeta insularis possibly, do the same. Milner,^ in 

 1870, writes that Belostoma grande captures and eats fi^shes. Miss 

 Onnerod,'" in 1878, describes how Ranatra linearis attacks fishes; the 

 same year Peck'^ called attention to the destruction of the eggs of carp 

 by the same insect. Turner,'^ ''' the next year, mentions the killing of 

 young sticklebacks in an aquarium by Belostoma. Leonard'^ notices 

 the showing at the Edinburgh Fisheries Exhibition in 1882 of a prep- 

 aration by Hugh D. McGovern, of Brooklyn, N. Y., of a year-old trout 

 "surmounted by the fish-eating bug, Belostoma grandis," which was in 

 the act of killing the fish by piercing its head ; aiul Tod<l'^ the same 

 year describes how a Belostoma, about three-quarters of an inch long, 

 was seen to vanquish a fish three or four times its own length. Uhler,'" 

 in 1884, states that Ranatra destroys the eggs of fishes, and sometimes 

 attacks the young fishes themselves and sucks their blood. "Writing of 

 Belostoma grande^ the giant species of this genus that is found in trop- 

 ical America, he states that "it is a formidable monster in the pools of 



' Superior figures refer to the citations of literature at the end of this article. 

 Bull. TJ. S. F. C. 1886 23 



