712 On Aquatic Carnivorous Coleoptera or Dytiscide 
1115. Megadytes gravidus, n. sp.—Ovalis, latus, antertus angustatus, sat con- 
vexus, supra olivaceo-niger, capite anterius prothoraceque ad latera testaceis, elytris 
vitta intramarginali obsoletissima, fere tantum ad basin distinguenda ; subtus niger, 
pedibus quatuor anterioribus rufis, tarsis intermediis piceis; pedibus posterioribus 
piceis, tibiis superne rufescentibus, femoribus nigris ; elytrorum epipleuris sat latis. 
Long. 33, lat. 193 m.m. 
I am acquainted only with the female of this species, which shows no trace of 
any sexual sculpture. 
The species is probably very closely allied to those preceding, especially to C. 
robustus, but the very obsolete lateral band of the elytra if constant, will render it 
easily distinguishable. 
Brazil. (Santa Cruz, Van Volxem). 1111. 
1116. Cybister costalis, Aubé, Trogus costalis, M. C. —Ovalis, latus, supra olivaceo- 
niger, capite anterius prothoraceque ad latera testaceis, elytris lateribus ante 
apicem sub-explanatis, vitta intramarginali, posterius lata sed parum determinata, 
testacea; subtus niger, epipleuris latioribus, pedibus anterioribus rufis, femoribus 
in medio nigricantibus, intermediis piceis, femoribus rufescentibus medio nigri- 
cantibus, posterioribus nigro-piceis, tibiis superne plus minusve rufescentibus. Long. 
31, lat. 19 m.m. 
The male has the front tarsi moderately large attaining 3 m. m.in the transverse 
direction; the intermediate feet have the three basal joints furnished with 
elongate sexual pubescence, and their claws elongate and unequal, the outer one 
being conspicuously thickened, and its under edge nearly straight. 
The female has a highly developed sexual sculpture, the thorax being entirely 
covered with deep irregular scratches, and the elytra bearing similar scratches on 
the greater part of the surface, the sutural portion, however, remains smeoth 
except at the base, and the explanate lateral portion is also smooth. 
In the Stet. Ent. Zeit. 1847, p. 52, will be found a long discussion on Fabricius’ 
species of this name ; the discussion being based on an examination of the Fabrician 
types in the collections at Kiel and Copenhagen ; the conclusion arrived at is that 
Dytiscus costalis, Fab., is not Cybister costalis, Aubé. Schaum’s discussion, however, 
was imperfect, inasmuch as he seems to have been unaware that the earliest 
description of Dytiscus costalis is contained in the Systema Entemologix, p. 230. 
(1775), not in Ent. Syst. I, p. 187, which dates only from 1792. If reference be 
made to the earlier description, it will be found that it agrees sufficiently with 
Aubé’s Cybister costalis to have justified Aubé in citing 1t. On the other hand, it 
would be improper to assign the name Dytiscus costalis, Fab., to Cybister dejeani, 
Aubé, as is suggested by Schaum on the authority of the type, for Fabricius says, 
“habitat Surinami, D. Yeats,” while C. dejeani is found only in the East Indies. 
