ANNULOSA JAVANICA. 29 
Capwt ut in genere Zaro CLainv. Thorax subquadratus canaliculatus postice angustior angulis anticis 
rotundatis. Corpus valde depressum. 
Oss. This genus is intermediate between Tarus Clairv. (Cymindis Lat.) and Helluo, Bon. ; 
from the latter it differs in the labrum not being acuminate, and from the former in the shape of 
the maxillary palpi and thorax. 
56. Bruacutatus. P. ater labro palpis antennis pedibus elytrorumque macula media ferrugineis elytris sulcato- 
strtatts. 
Long. corp. 4 
Caput atronitidum transversé punctatum facie levi bipunctata antice truncata. Thorax atronitidus punc- 
tatus. Elytra atra depressiuscula sulcata, sulcis profunde striatis macula versus basin ovali ferru- 
ginea. Corpus subtus atrum. 
Oss. This species may perhaps be found too near the Carabus Stigma of Fabricius, but cer- 
tainly is not the same with the Helluo distactus of Escholtz, described as a Javanese insect in 
Wiedemann’s Zoological Magazine ; although I suspect the latter to be also a Planetes, from 
what Dr. Escholtz says of the thorax being proportionally longer than in his Hellwo impictus, a 
species found in Bengal. Helluo distactus, differs from Planetes bimaculatus in being striated and 
having each stria marked with two rows of points. None of these species, however, are true 
Hellwones, and the mistake has arisen from the continental entomologists being so little ac- 
quainted with the original Hellwo of Bonelli, Hellwo costatus, which is a New Holland insect. 
Stirps. 2. HYDRADEPHAGA. Hyprocanruarr Lat. 
In the Geodephaga the binary subdivision of the groupe is not very distinct, because the cha- 
racteristic marks of each subdivision insensibly pass into each other. In this stirps of aquatic 
carnivorous insects it is however different, for the binary subdivision is remarkably distinct, 
and I know as yet of no insect which can satisfactorily fill up the hiatus that occurs between 
the Gyrini of Linnzeus and his Dytisci. 
The larvae of the Hydradephaga differ from those of Geodephaga in being truly aquatic, and 
therefore breathing by tracheal branchiae. Their prothorax also, or that segment of the body 
which corresponds with what is usually called the thorax of the perfect insect, is not of a 
more corneous texture than the other segments. 
I shall not at present attempt to divide the Hydradephaga into families, but content myself 
with giving the following approximation to a natural arrangement. The genus Hoplitus of 
Clairville seems to form the type of a family which I have not here ventured to designate. 
Hy pravepuaca. ‘amilia. 
1, Normal groupe, 
Pedes antici longi, —_—____—_—_- ]. Gyrinide. 
Antennz breves. 
Gyrinus Lin. 
2. Aberrant groupe. 2 2 ae ae 
Pedes antici breves, § 
Antenne setacez lineares. ( ne Sie SES eee inl Ay iscides 
Dyrtiscus Lin. 
__ 5 * x * 
Fam, 
