734 On Aquatic Carnivorous Coleoptera or Dytiscada. 
1147. Cybister explanatus, Lec., Trogus explanatus, M.C.—Ovalis, convexus, 
parum iatus, supra olivaceus, capite anterius prothoraceque ad latera testaceis, 
elytris margine externo, (cum epipleuris) late testaceo ; subtus ferrugineus, in medio 
plus minusve olivescens, pedibus quatuor anterioribus testaceis, tarsis intermediis 
picescentibus, pedibus posterioribus ferrugineis, tarsis magis picescentibus, femori- 
bus angulo externo posteriore spinoso-acuto ; elytrorum epipleuris versus apicem 
sat latis et planatis Long. 27, lat. 142 m.m. 
The male has the anterior tarsi moderately large ; the intermediate tarsi have 
the three basal joints with long sexual hairs beneath, there is a slight development 
on the fourth joint of sexual pubescence, and on the fifth joint the setze have under- 
gone a partial transformation into long sexual pubescence. The female has fine 
sexual sculpture largely distributed over the thorax and head, but none at all on 
the wing-cases. Both male and female have in the hollow near the articulation of 
the swimming legs four or five short, coarse folds or ridges, these are better developed 
in the male than in the female. 
This is a very distinct species bearing a superficial resemblance to Cybister ellip- 
ticus Lec., (No. 1120). It has a tendency to development of yellow colour along the 
anterior and posterior margins of the thorax. 
North America. (California). 1078. 
1148. Cybister reichei, Aubé, Trogus reichei, M.C.—Minor, ovalis, parum con- 
vexus, fere angustus, nitidus, capite olivaceo, anterius late testaceo, prothorace ad 
latera et ad marginem anteriorem testaceo, basi in medio late olivaceo ,elytris olivaceis, 
late testaceo-cinctis ; corpore subtus testaceo, pectore in medio prosternique processu 
obscurioribus, tarsis intermediis, tibiis tarsisque posterioribus piceo-rufis ; elytrorum 
epipleuris versus apicem latis et planatis; trochanteribus posterioribus apice libero, 
spinoso-acuto. Long. 20, lat. 94 m.m. 
The male has the anterior tarsi small; the intermediate feet with the three basal 
joints largely furnished beneath with rather short sexual hairs, and their claws a 
little elongate. 
The female has fine, short, distant scratches on the basal portion of the wing-case, 
and on the thorax. 
This little species cannot be confounded with any but the following one on account 
of the spinose posterior trochanters. The extent of the dark colour on the thorax 
is no doubt variable ; the ye!low band of the elytra does not terminate in a point 
at the suture, but is joined distinctly to the band on the other wing-case. 
There is some doubt as to the habitat of this little known species. Aubé 
was acquainted with only two individuals, one of which was said to be from Brazil 
the other from Senegal. JI have myself seen only two individuals, a male from 
Chevrolat’s collection, labelled “‘ Egypte, Flourens,” and a female in my own collection. 
