156 THE ENTOMOLOGIST. 



pp. 22-4, pi. XV. figs. 1-6) gives some reasonably good figures 

 with the name of the " broad waterbug with the two trap- claws 

 and the posterior air-tubes." The present name of " water- 

 scorpion " is that now used, or its equivalent, in almost all 

 European countries. 



Nepa cinerea occurs more or less commonly all over lowland 

 Britain. 



The metamorphoses were partially figured by De Geer in 

 1773, while figures of nymphs will be found in most "aquarium" 

 books ; the ova are figured by Dufour, Sharp, &c. The latter 

 are oval, terminated by seven filaments, and are inserted in the 

 stems of water-plants. 



Eanatra linearis.* 



The stridulation of an American species has been described 

 lately by J. E. de la Torre Bueno (1905, ' Canadian Entomologist,' 

 xxxvii. 85-7, figs. 5-11). " Two opposing rasps, one on coxa near 

 base with longitudinal striations, the other on inner surface of 

 cephalic margin of lateral plate of cosal cavity, which plate, by 

 its thinness, must act somewhat in the nature of a sounding- 

 board." Both adults and nymphs stridulate, and underwater as 

 well as out of it. 



The earliest representation of Ratiatra is also in Moufet 

 (p. 321) — in a characteristic attitude — where it is termed 

 " Locusta " ; in 1693 Swammerdam (* Historia Insectorum,' 

 p. 85) calls it " Scoiyius (!) aquaticus." Apparently, however, 

 Aldrovandus, in 1602 (' De Animalibus Insectis,' a huge work I 

 do not possess), refers to it under the name of " Tipula aquatica'' ; 

 the true Tipula (or rather Tippida) of the ancients was, how- 

 ever, probably a Gerrid (almost certainly not a dipteron as 

 Linngeus thought). Frisch in 1728 (vi. pp. 24-5, pi. xvi. figs. 

 1-6) terms it the " big narrow waterbug with the trap-claws and 

 posterior air-tubes"; according to him the Italians called it 

 "Cavalluccio."t 



The metamorphoses of Ranatra were well figured by Geoffroy 



=■' The etymology of Ranatra is uncertain, possibly a portmanteau word 

 from rana and atra, " a frog " and " black." A fish {Lophius piscatorius) 

 was called " Rana marina" by Cicero. 



f The earliest representation of Notonecta is also in Moufet. On p. 320 

 he says : — " Notonecta we call a certain aquatic insect which swims not on its 

 belly like the others, but lying on its back, from which men have probably 

 learnt to hyptionecticate — that is, their skill of swimming supinely " ! Moufet 

 apparently recognized the remarkable colour variation of N. glauca, for he 

 says: — "Of these, in some the eyes, scapulae, and body are blackish; in 

 others greenish, in others bronzy, in others pitchy ; for rarely seem two of 

 the same colouring, so varied is the nature of their pattern." Four figures 

 , are shown, three representing more or less typical glauca, with vars. macu- 

 lata and marginata, the fourth a nymph. In Switzerland the " boatfly," 

 according to Frisch, is called " glyssling," from its shining appearance when 

 covered with air-bubbles (from ''gleissen "). 



