•584 On Aquatic Carnivorous Coleoptera or Dijtiscidce. 



Groitp 11. (Nos. 865 to 868). 



Elytra with a submarginal stria and with seven or eight other striie on 



each. 



The striae absent are those neur the suture, but although the species agree fairly 

 in this respect, it is pretty certain they are not really allied to one another ; No. 

 867 indeed seems by the nature of the coxal lines to approximate to C. australis 

 of the first or estriate group; and No. 868 is more probably allied to No. 848 

 (eighth group). 



865. Copelatus chevrolati, Aube, M.C. — Oralis, elongatus, subdepressus, subtu.s 

 nigro-piceus, capite thoraceque rufescentibus, hoc lateribus dilutioribus, elytris 

 magis castaneis ; prothorace fere Isevi (in femina ad latera subtiliter strigoso) ; elytris 

 striis octo subtilibus, alternis posterius abbreviatis, aliaque marginali anterius 

 abbreviata. Long. 6, lat. 31 m.m. 



The male has the front and middle tarsi a good deal dilated, the front tibite 

 nearly simple ; the female has the sides of the thorax covered over a broad space 

 ■with fine anastomosing striae. 



North America. (California, Ai-izona, Texas, Kansas, Lake Superior, sfec. Crotch). 043. 



• 866. Copelatus validus, n. sp. — Oblongo-ovalis, sat latus, depressus, nitidus, niger, 

 antennis pedibusque rufis, prothorace lateribus elytrorumque apice dilutioribus ; 

 elvtris striis octo ante apicem desinentibus, prima a sutura remota, secunda disin- 

 teorata, aliaque marginali anterius et posterius abbreviata. Long. Tj', lat. 4 m.m. 



I have seen but a single individual ; it is a female, and has the sides of the thorax 

 rather densely covered with elongate scratches, but the disc is quite smooth ; a 

 rather small area near the side of each wing case also is rather closely covered 

 with distinct scratches. 



This species seems to be a large and dark-coloured one ; the first stria is about as 

 far from the suture as the width of the first, second, third, and fourth interstices 

 too-ether ; the second sti'ia is disintegrated and rudimentary, the second, fourth 

 and sixth are considerably shorter than the others, and stop short about two-thirds 

 of the length of the wing cases, the first, third, fifth, seventh and eighth are longer, 

 but still stop short a good distance before the apex ; at the base the alternate 

 striaj are more or less abbreviated : the submarginal stria is short and placed about 

 the middle of the length. 



Central America, (Chontales, T. Belt). 1159. 



