618 On Aquatic Carnivorous Cohoptcra or Dytiscidce. 



piceis, vertice vage piceo-maculato ; corpore supra deusius subtiliter reticulato, 

 subtus striijosulo, prosterno piceo. Long. 14, lat. 8 m.ni. 



The male has the three basal joints of the ircnt and middle tarsi greatly incrassate 

 and but Jiitle compressed, and furnished beneath with four series of large palettes, 

 and with very long marginal hairs with curled extremities, they have a smaU basal 

 patch of glandular pubescence ; the front claws are long and rather sknder, abruptly 

 bent at the base, and unequal, the anterior one being considerably smaller than the 

 posterior ; the fourth and fifth joints of the middle feet are very elongate, and 

 the claws are thick and unequal, the outer one being much longer and thicker than 

 the inner : the female has a small developmeiit of rugose sculpture, along the two 

 outer lines of subserial punctures on the elytra. 



Europe, (Italy and Corsica). 892. 



946. Colymbetes notaticollis, Aube, Rhnntus notaticollis, M.C. — Ovalis, sat 

 convexus, nitidus, subtus niger, prosterno testaceo, supra testaceus, vertice nigro- 

 variegato, thorace disco plaga transversa nigra, elytris creberrime nigroirroiatis, 

 antcnnis pudibusque rufis, illis extrorsura fuscescentibus, femoribus jjosterioribus 

 j)lus uiinusve picescentibus ; elytris creberrime tequaliter reticulatis : prothorace 

 margine laterali conspicue elevato. Long. lOi, lat. 5^ m.m. 



The male has the basal joints of the front tarsi incrassate and much compressed 

 and furnis'ned beneath with four rows of rather small palettes, the marginal hairs 

 are but little developed, and their extremities are not curled ; the claws are 

 moderately long and about equal; the middle tarsi are clothed beneath in a manner 

 similar to the front ones, and their claws are short and of about equal lengths, the 

 outer being however stouter than the inner. 



The species is very similar to Dytiscus notatus ; but the entirely black ventral 

 segments, and the fact that the spots of the elytra are so disposed as not to leave 

 the least trace of the two vein-like yellow lines which may be generally seen in 

 D. notatus, allow it to be easily distinguished ; besides this it wants the dense 

 strigulose sculpture seen on the basal portion of the elytra of D. notatus, and has 

 the male tarsi less dilated, their under clothing much less developed, and their 

 claws shorter and nearly equal, and the side margin of the prothorax in both sexes 

 more distinct: it is really much closer allied to D. bistriatus (No. 949), from which 

 it is distinguished only by the black mark of the thorax being on the disc instead 

 of at the base, and by the male tarsi being rather less developed. 



Europe, and Eastern Siberia, (Sweden, Finland, Northern Germany, Amurland). 893. 



947. Dytiscus notatus. Fab., Rliautus notatus, M.C. — Ovalis, sat convexus, 

 nitidus, subtus niger, prosterno laminaque communi coxarum posticarum testaceis, 

 abdomiue maris nigro, segmentis rufo-fasciatis, teminse rufo lateraliter nigro- 



