706 On Aquatic Carnivorous Coleoptera or Dytiscide. 
The species varies much in size and minute details, but I can see no signs of specific 
distinction. It cannot be mistaken for any other. 
Chili. 1100. 
1104. Cybister glaucus, Brullé, Zrogus glaucus, M.C_—Ovalis, subdepresssus, 
anterius angustatus, nitidus, levigatus, supra olivaceus, capite anterius parum argute 
testaceo, thorace elytrisque lateribus plus minusve vage ferrugineo-tinctis ; subtus 
vel piceus vel nigricans, pedibus quatuor anterioribus rufis, posterioribus vel ferru- 
gineis vel nigris; femoribus posterioribus angulo externo minutissime acuto vel 
recto. Long. 28, lat. 16 m.m. 
The male front tarsi are small, attaining only 2 m.m. in the transverse direction ; 
the intermediate tarsi have elongate sexual hairs on the basal joint, and also a few 
on the extreme base of the following jeint. The female appears to be quite with- 
out sexual developments, but under a powerful lens traces of a rudimentary 
sexual sculpture may generally be found, consisting of a very fine punctuation, 
more or less mixed with excessively fine scratches, along the middle of the wing- 
cases near the base. 
This species also appears to be a variable one; there may be roughly said to be 
two forms, one in which the colour of the upper and under surface and the hind legs 
are tinctured with ferruginous, and another in which the colour is nearly black 
with olive reflections ; the former of the two forms generally has the apical angle 
of the femora more acute, and the females have the sexual sculpture more obsolete 
than in the other variety ; but these characters are variable and indicate no specific 
distinction. 
South America ; especially in the south-east ; Buenos Ayres, Monte Video ; Bolivia (fide Mus. Castle- 
nau). 1101. 
Group 2. 
1105. Dytiscus latus, Fab., Trogus latus, M.C.—Ovalis, crassus, sat convexus, 
seepe ad basin elytrorum subsulcatus, olivaceus, capite anterlus vage ferrugineo ; 
subtus niger, prosterno in medio olivaceo ; pedibus quatuor anterioribus rufo.obscuris, 
posterioribus piceis: antennis parum gracilibus. Long, 22, lat. 13 m.m. 
The male has the front tarsi quite small, attaining only 1; m.m in the transverse 
direction, their fringing hairs at the heel are short and placed very near the palettes 
so that there is no pubescent area; the intermediate tarsi have a narrow line of 
quite short sexual pubescence along the underside of the basal joint, and there may 
‘be traces of a similar line on the following joint; the inner claw on the hind feet 
is much smaller and shorter than the outer one. The female has a sexual sculture 
