On Aquatic Carnivorous Coleoptera or Dytiscide. 685 
1072. Cithionectes optatus, n. sp.—Latus, anterius angustatus, subtus con- 
vexus, nitidus, niger, capite antice, vertice maculis duabus, prothorace ad latera, 
elytris signaturis transversim positis, antennis pedibusque anterioribus testaceis, 
tibiis tarsisque posterioribus picescentibus; elytris epipleuris latis. Long. 12, 
Jat. 7 m.m. 
Fem., elytris versis basin in medio subtilissime punctulatis. 
This species by its broad form, narrowed in front, by its markings and general 
facies, presents a great resemblance to the South American Dytiscus interruptus (No. 
1066) and its allies. ‘The markings of the wing-cases consist of some spots close to 
the base, forming a transverse band, and some other spots just behind the middle 
forming another irregular band most distinct near the sides, and an apical yellow 
mark which is much interrupted with black ; the lateral margins also are vaguely 
yellow. The sexual sculpture of the female elytra is so very slight, that it may 
very readily pass unnoticed. J have seen only two females, which differ a good 
deal in the distinctness of the yellow marks on the elytra. 
The specimen in my own collection was labelled in Mr. Saunders’ collection, 
“W. Afr.”, the individual in M. de Bonvouloir’s, ‘Guinée portugaise.” 
Western tropical Africa, (Guinea). 975. 
I. 72.—Genus SANDRACOTTUS. 
Coxal lines obliterated, so that no supra-articular border is visible; middle 
femora with setz of moderate length. LElytra variegate with large yellow and 
black marks. 
Ten species* are known, extending from India through Malasia to Australia. 
1073. Sandracottus hunteri, (Crotch,) Hydaticus fasciatus, M.C.—Ovalis, sat 
Jatus et convexus, nitidus, subtus niger, supra testaceus, vertice summo, prothorace 
anterius et posterius in medio, elytris sutura, fasciis duabus transversis irregularibus 
punctisque longitudinaliter dispositis nigris, antennis pedibusque anterioribus 
testaceis, pedibus posterioribus nigricantibus, femoribus seepe rufescentibus. 
Long. 122, lat. 8 m.m. 
In the male the smaller palettes of the front feet are well developed, so that the 
three larger palettes, which are only of moderate size and differ but little inter se, 
* Hydaticus baeri, Regt. (No. 1307 huj. op.), near No. 1073; Manilla, should also be referred to this 
genus ; whether Colymbetes clairvillei, Mont. (No. 1217), New Caledonia, be a Sandracottus is doubtful. 
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