614 On Aquatic Carnivorous Coleoptera or Dyliscidoe, 



The male characters seem to be the same as those of Colymbetes divisus (No. 

 930) ; in the female the reticulation on the sides of the elytra near the middle is 

 deeper, and in some individuals there is also a development of patches of this 

 deeper reticulation along the lines of indistinct serial punctures. 



North America, (Hermit Lake). 882. 



935. Colymbetes hmoi&ins, 'R&vy\s, Rhantus hinotatus, M.C. — Ovalis, robustus, 

 sat convexus, subojmcus, subtus niger, prosterno riivo abdominis lateribus rufo- 

 variegatis, supra testaceo vcrtice nigro-variegato, prothorace medio maculis duabus 

 nigris, elytris creberrime nigro-irroratis, antennis pedibnsque testaceis, illis extror- 

 Bum leviter infuscatis ; prothorace margine laterali tenui anterius obsoleto ; elytris 

 creberrime subtilissimeque reticulatis ; pedibus posterioribus crassis, unguiculo 

 interno quam externo duplo longiore. Long. 11, lat. 6 m.m. 



The male has the front and middle tarsi a good deal incrassate, and rather 

 strongly compre.^sed, and lurnished beneath with four rows of rather large palettes, 

 the claws of the from, feet are rather short, and are bisinuate beneath, the anterior 

 being rather the longer ; on the middle feet the outer claw is a good deal longer 

 than the abruptly curved inner one. 



Though this species much resembles the shorter and more robust forms of li. 

 plebeius, it is abundantly distinct, and besides the characters mentioned above has 

 the side wings of the metasternuin shorter. It varies a good deal in size and form, 

 and a little in sculpture. The females from the United States have the reticulation 

 on the middle and front part of the outer portion of the elytra coarse, but in the 

 specimens from Mexico I find only slight traces of this coarser sculpture. 



Mexico, Guatemala, Western United States, (Peru ?). 883. 



936. Colymbetes mexicanus, Cast., Rhantus mexicauus, M.C. — Ovalis, robustus, 

 sat convexus, subopacus, subtus niger, prosterno rufo, abdominis lateribus rufo- 

 variegatis, capite thoraceque rufis, illo vertice nigro-variegato, hoc maculis duabus 

 parvis nigris, elytris nigricantibus, margine laterali apiceque testaceis, hoc nigro- 

 in-orato, antennis pedibusque i-ufis, illis extrorsum leviter infuscatis ; prothorace 

 margine laterali tenui anterius obsoleto ; elytris omnium densissime subtilissime- 

 que reticulatis ; pedibus posterioribus crassis, unguiculo interno quam externo vix 

 duplo longiore. Long. 11, lat. 6 m.m. 



This species is very closely allied to the preceding one, but has the elytra black, 

 and their sculpture still denser and finer. The male characters seem to be nearly 

 the same. 1 find no difference in the sculpture of the females. 



Mexico ; Guatemala. 884. 



