112 H YDR ADEPH AG A — DYTISCID AE. 



ending in a sharp point ; last joint of lahial palpi scarcely 

 longer than the second, pointed ; body oval, Hatly arched. 



Lacco2)hilus, Leach. 



h. Scutellum visible. 



I. Posterior tarsal claws unequal. 



1, Body rather flat. 



Inner claw on posterior tarsi three times as long as 

 outer one ; second joint of labial i)alpi fully as long as the 

 last one. Colymlctes, Clairv. 



2. Body convex. 



Inner claw on posterior tarsi rather longer than outer 

 one ; second joint of labial palpi rather shorter than, or as 

 long as the last one ; each elytron with two transparent 

 light spots, more or less apparent. Ili/bius, Er. 



II, Posterior tarsal claws equal. 



J. Front pairs of tarsi in male strongly dilated, not 

 compressed, and l)earing four rows of large sucker- 

 cups beneath. 

 Body elongate, nuich narrowed behind ; elytra pointed 

 at apex. Lioptertis, Eschsch. 



2, Anterior male tarsi slightly dilated and bearing 

 small sucker-cups beneath. 



Body oval, more or less convex. Anterior claws of 

 female' always simple and similar, those of male often dis- 

 similar ; elytra with three irregular rows of punctures. 



Ayahvs, Leach. 



]i. First three joints of anterior male tarsi forming a 

 roundish plate, fringed with hair and covered beneath 

 with sucking-cups and larger suckers. 



a. Posterior claws nearly equal in size, moveable. 



Under-side of anterior male tarsi with a large sucker at 

 base, another nearly as large rather before this ancl a 

 number of equal, small cups ; elytra oblong oval ; posterior 

 tarsi fringed with long hairs on both sides in male, on 

 inner-side only in female. Intermediate tarsi of male 

 dilated. Upper-side of male smooth, of female furrowed. 



Dytiscus, Lin. 



h. Posterior claws uue(pial, the larger one fixed. 



