On Aquatic. Carnivorous Coleoptera or Dytiscidoe. 601 



I. .^g.— Genus COPTOTOMUS. 



Palpi with their terminal joints a little incrassate, and rather deeply notched at 

 the extremity ; prosternum thickened along the middle. 

 The three species* are North American. 



910. Coptutomus obscurus, n. sp. — Ovalis, convuxus, minus elongatus, nitidus, 

 testaceus, subtus rufo-testaceus, vertice, prothorace anterius et posterius in medio 

 elytrisque vittis irregularibus plus minusve coalescentibus nigris ; corpore supra 

 crebre subtiliter punctato ; prosterno in medio crasso, anterius perpendiculari ; 

 coxis posterioribus magnis. Long. 7, lat. 8.i m.m. 



The male has the basal joints of the front and middle tarsi a little incrassate, and 

 furnished beneath with moderately long hairs, bearing small palettes ; the claws on 

 the front feet are slender and moderately long, the front one liaving beneath in the 

 middle a very minute thickening, while the hinder ha^ tlie basal portion more 

 distinctly emarginate ; there is a slight difference in the sculpture of the elytra in 

 the two sexes ; in the female the punctuation on the basal portion of the elytra is 

 more distinct and regular than in the male, the punctures being slightly elongated 

 so as to form excessively short strire. 



The species is excessively similar to the two following, but is smaller and darker 

 in colour, especially beneath, and has the hind coxae more free from sculpture, and 

 their front border nearer to the middle coxal cavities ; the sexual distinctions are 

 also less conspicuous. 



Nortli America, (Texas, Florida'". 910. 



911. Dytiscus interrogatus. Fab., Coptotoniits interroriutu.^, M.C. — Ovalis, con- 

 vexus, sat elongatus, nitidus, testaceus, vertice, thorace anterius et posterius in 

 medio, elytrisque vittis irregularibus plus minusve coalescentibus nigris ; corpore 

 supra crebre subtiliter punctato ; prosterno in medio crasso, anterius perpendiculari, 

 coxis posterioribus magnis, subrugosulis. Long. 8, lat. 4 m.m. 



The male has the basal joints of the front and middle tarsi a little incrassate, and 

 furnished beneath with long hairs, bearing small palettes, the claws of the front, 

 feet are rather long, and have their basal portion slightly emarginate beneath, this 

 is more distinct on the posterior than on the anterior one. In the female the basal 



* The two following species unknown to me are pi-oliably closely allieil to, if distinct from, one or 

 other of those described in the text. Coptotomus difficilis, Lee, (No. \ili Inij. op.)? No. 911 var. 

 North America. — Coptotomus serripalpus, Say, (No. 1273); Mexico. 



