THE WATER-SCORPION BOAT-FLY. 243 



carry it off in despite of all the struggles of the fish * ; 

 and the editors of the Entomologia Edinensis inform 

 us, in speaking of the rapacity of the Dyticidce in 

 the larva state, that they " observed one of the larger 

 kinds transfix and suck out the juices of thirteen 

 well-grown tadpoles, in a single day." 



I must not, however, dwell in this manner on aU 

 the insect inhabitants of the water, else you might 

 dread I was about to become, as Dogberry would 

 word it, " as tedious as a king." But I may mention, 

 that if you expand the ashy-coloured elytra of one 

 common insect, the water- scorpion {Nepa cinerea), 

 you wUl be pleased to find, under so hard and dusky 

 an exterior, a soft and delicate pair of wings, folded 

 on a ground of a pecuHar shade of scarlet. If you 

 watch another, which is here very abundant, the 

 boat-fly (Notonecta glanca), lying on his back, and 

 using his long and dehcately-fringed feet as oars to 

 impel him along, beware of taking him in your hand, 

 or you may find by experience, as I have done, that 

 the wound inflicted by his rostrum is both sharp and 



* For an interesting fact with respect to our Irish three-spined 

 stickleback, we are indebted to the obsen'ation of W. Tliompsoii, 

 Esq., Vice-President of our Natural History Society. He has pointed 

 out the differential characters between it and the three English spe- 

 cies described by Mr. Yarrell, and shown its identity with the Gn*- 

 terosteus brachi/centrusoi Cuvier, found in the brooks of Tuscany. — 

 Vide Proceedings of Linncan lioeieti/, in the London and Edinburgh 

 Phil. Mag. and Journal of Science, vol. v. p. 229. 



R 2 



