638 On Aquatic Carnivorous Coleoptera or DytiscidcB. 



988. Dytiscus verticalis, Say, M.C. — Latus et robustus, parum nitidus, subtus 

 piceus, supra nigricans, prothorace elytrisque flavo-marginatis, antennis piceo-iufis, 

 basi rufo, pedibus piceis femoribus quatuor anterioribus rufis ; dytrorum margine 

 flavo ad finem angusto et ab apice remoto ; pedibus posterioribus robustis ; prosterni 

 processu angustulo sat elongato : coxarum processubus latis, rotundatis ; labro in 

 medio anguste sed profuude emarginato. Long. 32, lat. 17 m.m. 



Mas, prothorace fere aequaliter transversim convexo, elytris etiam ad apicem 

 fere impunctatis. 



Fern., prothorace intra marginem lateral em impresso, capite in medio prothoracis- 

 que lateribus crebre punctatis, elytris sparsim subtiliter punctatis. 



The male has the small palettes on the front tai'si highly developed ; those on 

 the middle tarsi are also well developed, though not quite so large as on the front 

 feet. 



Except in size the species exhibits very little variation. 



The large size, and broad form, and the nature of the apical yellow fascia of the 

 elytra give this species some resemblance to D. harrisi (No. 1,004), D. verticalis is 

 however considerably smaller, has the thorax in front and behind without distinct 

 yellow margin, the notch in the middle of the labrum longer, besides numerous 

 other less conspicuous differences. 



Eastern North America, (Cauada, Lake Superior, New York, Penn.sylvauia). 939. 



989. Dytiscus marginicollis, Lee, M.C. — Elongato-ovalis, elytris posterius rotun- 

 datis, parum truncatis, subtus testaceus, parum nigro-variegatus, supra brunneo- 

 olivaceus (?), prothorace limbo omni late flavo-marginato, elytris margine flavo ad 

 apicem lato et minus obsoleto, antennis pedibusque rufis, tibiis tarsisque posteri- 

 oribus obscurioribus ; pedibus posterioribus gracilibus ; prosterni processu elongato ; 

 coxarum processubus obtusis. Long. 29, lat. 14 m.m. 



Mas, nitidus, elytris ad apicem perparum punctatis. 



This species is only very imperfectly known to me, the two males before me 

 being in very bad condition. The broad yellow margins on its thorax, and the 

 general form cause it to resemble the Mexican Dytiscus habilis, from which how- 

 ever it is distinguished by its parallel prostei-nal process, and by its more divergent 

 coxal processes, with less rounded apices, and its more slender swimming legs. The 

 front and middle tarsi seem to be extremely similar to those of D. habilis. 



So far as I can judge, it would seem that the species is about intermediate be- 

 tween D. habilis, and D. sublimbatus. 



North America, (Califoniia and Kansas, Crotch.). 1140. 



990. Dytiscus sublimbatus, Lee, M.C. — Subtus testaceus, metasterno in medio 

 coxarumque processubus picescentibus, supra niger, prothorace limbo omni flavo- 



