638 On Aquatic Carnivorous Coleoptera or Dytiscide. 
988, Dytiscus verticalis, Say, M.C.—Latus et robustus, parum nitidus, subtus 
piceus, supra nigricans, prothorace elytrisque flavo-marginatis, antennis piceo-rufis, 
basi rufo, pedibus piceis femoribus quatuor anterioribus rufis; elytrorum margine 
flavo ad finem angusto et ab apice remoto ; pedibus posterioribus robustis ; prosterni 
processu angustulo sat elongato; coxarum processubus latis, rotundatis ; labro im 
medio anguste sed profunde emarginato, Long. 32, lat. 17 m.m. 
Mas, prothorace fere eequaliter transversim convexo, elytris etiam ad apicem 
fere impunctatis. 
Fem., prothorace intra marginem lateralem impresso, capite in medio prothoracis- 
que lateribus crebre punctatis, elytris sparsim subtiliter punctatis. 
The male has the small palettes on the front tarsi 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, (Canada, Lake Superior, New York, Pennsylvania). 939. 
989. Dytiscus marginicollis, Lec., 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 betore 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 prosternal 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, (California and Kansas, Crotch.). 1140. 
990. Dytiscus sublimbatus, Lec., M.C.-—Subtus testaceus, metasterno in medio - 
coxarumque processubus picescentibus, supra niger, prothorace limbo omni flavo- 
