650 On Aquatic Carnivorous Coleoptera or Dytiscide. 
Group 1. 
1006. Dytiscus seminiger, de Geer, Hydaticus seminiger, M. C.—Ovalis, sat latus, 
parum nitidus, niger, subtus prosterno anterius capiteque in medio testaceis, supra 
capite thoraceque rufis, illo in vertice nigro rufo-bimaculato, hoc basi in medio 
extensius nigricante, elytris margine laterali flavo ; antennis pedibusque anterloribus 
rufis, tibiis intermediis piceis, pedibus posterioribus nigro-piceis, unguiculo interno 
quam externo vix duplo longiore. Long. 13, lat. 72 mm. 
In the male of the species, the fringing hairs of the front tarsi are rather short, 
and the palettes differ little inter se in size, those at the base not being very large, 
the claws are rather stout, are abruptly curved at the base and are sinuate beneath ; 
the middle tarsi are broadly dilated and the basal patch of dense rough seta is 
rather large. The female has some coarse impressions on the thorax near the sides, 
and a few similar marks at the side of each wing-case near the front. 
The species seems to vary but little, the female often has the black colour on 
the thorax more extensive than in the male, so that it occasionally nearly attains 
the front margin, the yellow lateral stripe of the elytra 1s, too, generally more dis- 
tinct in its terminal portion than it is in the male. 
Europe. (Sweden ; Finland, 61°, Sahlberg ; England ; France ; Germany ; Alpes Maritimes, sec. Bedell). 
1038. 
1007. Hydaticus modestus, n. sp.—Oblongo-ovalis, parum latus, subtus nigro- 
piceus, capite prosternoque rufis, supra capite thoraceque rufis, illo in vertice nigro 
rufo-bimaculato, hoc basi in medio nigro, elytris nigris margine laterali punctisque 
transversis subbasalibus flavis, antennis pedibusque quatuor anterioribus rufis, 
pedibus posterioribus piceis, unguiculo interno quam externo haud duplo longiore, 
Long. 14, lat. 74 m.m. 
The male has the front tarsi rather large, their dems are rather long, are sud- 
denly bent at the base and are sinuate beneath ; the middle tarsi are broadly dilated, 
and the basal patch of dense rough setee is very large and conspicuous. 
I have seen only a single individual of the species (a male in very bad condition) ; 
it seems to be very closely allied to Dytiscus seminiger, and is extremely similar to it, 
but is of narrower form, the black colour at the base of the thorax is defnitely 
limited and does not reach quite so far forward as the middle, and there are faint 
indications of a transverse line of pale colour on the elytra near the base. The 
apices of the elytra are slightly sinuate, and in the female sex this 1s no doubt more 
conspicuous. In size and form it appears to be very similar to Hy daticus america-— 
nus (No. 1009), but seems to ke readily distinguished by the absence of yellow 
longitudinal lines on the wing-cases. 
North America. 1037. 
