630 On Aquatic Carnworous Coleoptera or Dytiscide. 
974. Colymbetes substrigatus, n. sp.—Ovalis, elongatus, sat convexus, nitidus, 
nigro-piceus, antennis palpis, capite anterius et in medio verticis thoraceque ad 
latera rufescentibus, elytris parum conspicue transversim testaceo-undulatis ; corpore 
sublevigato, elytris obsolete transversim strigosis, versus suturam leevigatis, punctis 
seriatis conspicuis, abdomine sutura secunda ventrali utrinque prope medium 
conspicue serratulo. Long. 16, lat. 8t m.m. 
The male has the basal joints of the front and middle tarsi slightly incrassate 
but greatly compressed, and furnished beneath with four series of rather small 
round palettes ; there is but little sexual difference of sculpture, the transverse strize 
are rather less distinct in the male than in the female. The species resembles 
Dytiscus fuscus, but is rather smaller and darker in colour than the average repre- 
sentatives of that species, and is very readily distinguished by its obsolete 
sculpture. 
Arabia. 921. 
975. Colymbetes piceus, Klug, M.C.—Ovalis, sat elongatus et convexus, nitidus, 
nigro-piceus, antennis palpis capite anterius et in medio verticis thoraceque ad 
latera rufescentibus, elytris parum conspicue transversim rufo-undulatis ; corpore 
sublevigato, elytrorum punctis seriatis conspicuis; abdomine sutura secunda 
ventrali utrinque prope medium conspicue serratulo. Long. 152, lat 8 m.m. 
This species is excessively closely allied to C. substrigatus, but is a little smaller 
and less elongate, and shows scarcely any rudiments of the transverse sculpture of 
the wing-cases ; it is also a little smaller and less elongate. The male characters 
seem to be quite the same, the female I have not seen. 
Sinai, 922. 
976. Colymbetes vagans, n. sp.—Ovalis, latior, convexus, nitidus, piceus, antennis 
pedibusque rufis, capite anterius et in medio verticis ferrugineo, prothorace elytrisque 
lateribus basi rufo-testaceis, his versus latera rufescentibus et transversim nlgro- 
irroratis ; corpore subleevigato, supra subtilissime punctulato, elytris punctis seriatis 
conspicuis, abdomine sutura secunda ventrali utrinque prope medium evidenter 
serratulo, Long. 15, lat. 8 m.m. 
_ This species is very closely allied to the preceding, but is distinguished by 
its broader, shorter form, and its more dilute colour. On the elytra near the sides 
towards the extremity,there may be detected traces of undulated transverse sculpture, 
which seems to arise rather from a peculiar arrangement of the very fine punctures, 
than from the existence of any distinct transverse strie. The hind legs are shorter 
and stouter than in the allied species. The male characters seem to be nearly the 
