10 Mr. W. S. Dallas's Notice 



from Ranatra ; for these fringes indicate a much greater velocity 

 of motion than is possessed by the other Ranatrce ; the short, 

 broad anal setae will act as a rudder, rendered necessary by the 

 increased activity of the animal, whilst the elongated anterior legs 

 being no longer requisite, and tending rather to impede its move- 

 ments, become contracted into more moderate dimensions. In- 

 deed, it appears to be a rule in the genus Ranatra that any increase 

 in the length of the caudal setee is accompanied by an increase, 

 although to a less extent, in the length of the anterior legs, and 

 probably a diminution of the activity of the animal. 



The second is a true Ranatra. 



Sp. 7. Ranatra gracilis. 



R. elongata, ferrugineo-fusca, obscura ; capite tuberculo acuto 

 inter oculos ; setis caudalibus brevibus, tenuibus ; abdomine 

 carinato, prosterno bisulcato ; pedibus quatuor posticis sub- 

 pilosis. 



Long. corp. lin. 12|. 



Linear-elongate, ferruginous brown, obscure. Head with an 

 acute tubercle between the eyes. Scutellum with two small pits 

 on the disc towards the apex. Elytra reaching beyond the base 

 of the apical segment of the abdomen. Caudal setae short, rather 

 longer than the head and thorax together, slender, very slightly 

 pilose externally. Abdomen beneath keeled, the keel not con- 

 tinued beyond the base of the posterior legs. Prosternuin with 

 two longitudinal furrows. Legs very long and slender, subpilose, 

 anterior thighs with six very faint teeth beneath at the base ; the 

 four posterior tibiae and tarsi simple. 



This species appears to be allied to the R.JHiformis, Fab., but 

 wants the grey rings on the legs mentioned in his description ; it 

 is also a much larger insect than that figured by Guerin under 

 that name, and has the caudal setae much shorter in proportion. 



Of the Homoptera, there are, as above mentioned, only two 

 species, both belonging to the genus Cercopis. 



Sp. 8. Cercopis fulviceps. 



C. capite, thoraceque fulvis, elytris nigro-rufis, corpore subtus, 

 pedibusque nigris. ? . 

 Long. lin. 10| (22 mill.) 



Head and thorax bright orange, shining, very finely punctured, 

 the latter with a narrow but very distinctly raised border. Scu- 



