TRANSACTIONS 



ENTOMOLOGICAL SOCIETY 



LONDON. 



I. DytiscidcB Darwiniance ; or, Descriptioiis of the Species 

 q/" Dy tiscidse collected Z*?/ Charles Darwin, Esq., M.A. 

 Sec. G. S. Sfc, in South America and Australia, during 

 his Voyage in H.M.S. Beagle. ^?/ Charles C. Babing- 

 TON, M. A., F. L. S., F. G. S., ^c. 



[Read 4th June, 1838,] 



At the request of my friend Mr. C. Darwin, I have examined 

 the species oi Dytiscidce collected by him during his voyage with 

 Captain Fitzroy in the Beagle, and have now the honour of sub- 

 mitting the following descriptions of them to the Entomological 

 Society. The specimens described very closely resemble some of 

 those which are natives of the British isles : but, after a minute 

 examination, a marked difference is always found to exist between 

 them and any European insects. 



Before proceeding to the descriptions, I propose to make a few 

 observations ; and in the first place I would draw attention to the 

 Cybister, which I have named 2-imgulatus. It has been observed 

 by Erichson, Curtis, Stephens, &c., that this genus has only one 

 immoveable claw to the posterior tarsi. Hei-e (PI. I. fig. la, \ h) 

 we find two clearly distinguishable claws both immoveable, and 

 apparently joined together at their base ; or rather perhaps we 

 ought to consider it as one claw very deeply divided into two 

 parts. This insect also differs from the usual structure of the 



VOL. III. B 



