.On Aquatic Carnivorous Coleoptcra or Dytiscidce. 579 



850. Copelatiis debilis, n. sp. — Ovalis, depressus, nltidus, piceo-testaceus, capite, 

 prothorace lateribus, elytrorum basi et apice, antennis pedibusque testaceis ; elytris 

 striis quinque elongatig, prima a sutura remota, striaque marginal! anterius ab- 

 breviata. Lonff. 4. lat. 2 m.m. 



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

 much curved inwardly and the basal portion slender : the upper surface is very 

 smooth except for the strise on the wing-cases : the female differs a little from the 

 male, the striae being slightly deeper, and there being a very fine and obsolete 

 punctuation on the upper surface, but no scratches. 



The species is of small size and cannot be very easily mistaken for any other, on 

 account of the number of the striae — five on eacli winof-case: the first of these is 

 quite twice as far from the suture as it is from the second stria ; then the three 

 inner interstices are of about the one width, the fourth, or outer one, being a little 

 narrower than the others ; the submarginal stria is elongate, but stops short a good 

 deal behind the shoulder. 



Central America, (Cliontales, Belt; S. Gerouimo, Guatemala, Champion). 1158. 



Group 10. (Nos. 851 to 864). 



Elytra with a submarginal stria and six other striae on each. 



In this group the strife are equidistant, and it is the n.lternate ones that are 

 wanting ; very frequently the first stria is much abbreviated in front, or indeed only 

 exists on the posterior portion of the wing-case. 



551. Copelatus marginatus (Wehncke), n. sp. — Ovalis, latiusculus, hand elongatus, 

 subdepressus, piceus, capite et prothoracis elytrorumque lateribus dilutioribus, 

 antennis pedibusque testaceis ; prothorace sublaevigato, ad angulos posteriores 

 subtilius punctulato ; elytris striis sex ad apicem prolongatis, interna posterius 

 tantum exstat, ceteris elongatis, aliaque marginali valde abbreviata. Long. 6, lat. 

 Z\ m.m. 



In the male the front and middle tarsi are a good deal dilated ; the basal portion 

 of the front tibia is quite slender, and its inner edge sinuate, the lower part of the 

 tibia is broad ; the elytra have a subobsolete punctuation, which in the female is 

 replaced by the numei'ous very short and extremely fine scratches. 



Australia, (Rockhamptoii, Port Deuison). G75. 



THANS. EOT. DUB. SOC. X.3., VOL. II. 4 F 



