678 On Aquatic Carnivorous Coleoptera or Dytiscide. 
same distance as the front one is from the front margin, and the hind one from the 
base ; in one of Aubé’s type specimens, these black marks however are somewhat 
diminished. 
Mexico. 962. 
1059. Acilius ornaticollis, Aubé, M.C.—Parum latus, nitidus, leevigatus, elytris 
punctis seriatis sat conspicuis, subtus rufo-testaceus, supra testaceus, vertice 
thoraceque transversim nigro-signatis, elytris nigro-irroratis, pone medium fascia 
transversa plus minusve conspicua nigra. Long. 11%, lat. 63 m.m. 
Mas, levigatus, nitidus. 
Fem., nitida, elytris ad basin in medio punctis elongatis sat subtilibus impressis. 
This species varies considerably in size, in the black marks of the upper surface, 
and somewhat in the sculpture of the femaies. The black marks on the thorax 
consist of a transverse line very near the front margin, and of a second one just 
behind the middle, this latter often more or less connected with a black basal 
line ; the front line is generally slightly interrupted in the middle, and is liable to 
be very much diminished, even broken up into three or four dashes; the post- 
medial mark is more or less distinctly biarcuate; and the basal black mark is 
sometimes quite absent. When these marks are very largely developed, the front 
one scarcely leaves any yellow colour at the front margin, and is connected at the 
sides with the post medial mark, and this latter may be nearly entirely confluent 
with the black basal mark. The elytra are sometimes much more covered with 
the black colour than at others, and the post-medial black band, never very con- 
spicuous, can occasionally be scarcely detected. The impressed short lines on the 
wing-cases of the female are sometimes a little coarser, and their extension in the 
posterior direction is a little variable, but there is never any indication of their 
presence on the prothorax. 
North America, (United States and Mexico.) 963. 
1060. Acilius succinctus, Aubé, M.C.—Sat convexus, nitidus, leevigatus, elytris 
puuctis seriatis sat conspicuis, prosterno ex parte majore testaceo,abdominis lateribus 
flavo-maculatis, supra testaceus, vertice prothoraceque transversim nigro-signatis, 
elytris nigro-irroratis, pone medium fascia transversa nigra, pedibus anterioribus 
testaceis, posterioribus rufescentibus, femoribus basi tibiisque extus nigricantibus. 
Long. 113, lat. 63 m.m. 
Mas, nitidus, levigatus. 
Fem., nitida, elytris ad basin punctis elongatis rudis impressis, prothorace 
utrinque punctis parum conspicuis. 
