On Aquatic Carnivorous Coleoptera or Dytiscida. 747 
Group 6. 
1169. Dytiscus reeselii, Fab., Trogus virens, M.C.—Ovalis, posterius conspicue 
latior, supra olivaceus, capite anterius prothoraceque lateribus testaceis, elytris vitta 
laterali versus apicem attenuata, et a margine laterali ‘separata, testacea ; corpore 
subtus testaceo, pectore in medio plus minusve brunneo, tarsis intermediis et tibiis 
tarsisque posterioribus piceis; femoribus posterioribus angulo externo acuto, 
subspinoso. Long. 34, lat. 184 m.m. 
The male has the claws on the intermediate feet a good deal longer than in the 
female, and unequal, the front one being much thicker and a little longer than the 
other; it has the uppersurface of the body smooth and shining, while in the 
female the thorax is covered with curved irregular depressions or scratches, and 
the wing-cases bear longitudinal scratches which anastomose here and there, a space 
at the apex remains, however, always smooth. On the undersurface the epipleure 
of the female are conspicuously fiattened just behind the shoulder, while at the 
same spot they are rounded in the male. 
In this species the yellow band of the elytra at the shoulder starts from quite the 
outer margin, but becomes thinner towards the extremity, and is in a gradual 
manner more and more separated from the outer margin, it becomes quite obsolete be- 
fore the apex, but at the apex the external margin is itself vaguely yellow, and the ex- 
tremity of the yellow band is only separated in a very vague manner from this terminal 
yellow colour. The colour of the undersurface varies somewhat, the infuscation of the 
breast along the middle being sometimes very slight, while at other times it is quite 
conspicuous, and when it is greatest the coxal processes become quite greenish or 
olivaceous in colour. The most remarkable variety, however, is one found in 
Portugal, it is of small size, being about 31 m.m. long, and the sexual characters 
differ remarkably from what is usual in the species, the female being quite smooth 
on the uppersurface, and the anterior tarsi of the male are unusually small, attain- 
ing only 23 m.m. in the transverse direction, the normal dimension being 34 m.m. 
This variety may be designated as var. lusitanicus, I have seen only three individuals 
of it, two females and one male found by d’Oliveira, it is worthy of remark that the 
intermediate tarsus on the left leg of the male is like that of a female, while the 
right foot is normal. 
The species does not extend its range to Britain or Scandinavia. The smooth 
variety of the female seems very rare, the only specimens I have seen of it come 
from Portugal. 
Cybister chaudoiri, Hoch., was founded on two females found at Lenkoran, and 
from the description and remarks of its describer it seems highly probable that it 
Is a variety of Dytiscus reeselii. 
Europe and Northern Africa. Northern France, Belgium, Germany, Portugal, Corsica, Italy, Greece, 
Corfu, Siberia, (East India ?) 
TRANS. ROY. DUB. 80C., N.S., VOL. I. 56 D 
