ANNULOSA JAVANICA. 31 
Fam. 4, DYTISCIDZ. 
The larvee of these insects have not the lateral branchial appendages of the Gyrinide, and 
are therefore much less scolopendriform. Indeed their sub-convyex and rather conical body 
with various other circumstances might, on a first view of them, make us place them out of 
their natural situation ; but their obvious analogy to the larvee of Hemerobii, as well as to the 
larvee of Geodephaga, will serve to make them known to the practical entomologist. 
There are few insects so voracious as the Dytiscide, and their power of moving at will either 
in the water, in the air, or on the earth, gives them ample means of satisfying their 
rapacity. 
} may in this place make the remark, that aquatic insects do not among themselves differ so 
much in form as terrestrial insects. It is not merely that they are fewer in species, and therefore 
may be expected to form fewer genera, but that the tropical genera of aquatic insects are much 
the same with our own, or at least are not so different from each other as the tropical and Euro- 
pean Geodephaga. Another remark to be made is, that aquatic insects are in general as large 
or larger with us than they are within the tropics. I know of no Hydrophilide larger than our 
Hydrophilus piceus; and the largest of the Dytiscide, that has ever come under my notice, is 
the D. latissimus of Sweden. The only exception to this remark among the Hydradephaga 
occurs in the Gyrinid@, as for instance in the genus Dineutus above described. 
Genus COLYMBETES Clairv. 
60. OcropEcim-macuLaTa. C. niger capite maculis tribus, thorace marginali, elytris vittéd marginali maculisque 
novem flavis. 
Long. corp. § 
Caput maculis tribus mediis Thoraxque macula marginali flavis. Elytra striis tribus punctorum obso- 
letissimorum, vitta marginali nec basin nec apicem attingente, maculis flavis tribus basalibus, 
quatuor mediis fasciam fere formantibus et duabus apicalibus. Corpus subtus nigrum abdominis late- 
ribus rufo-maculatis. | Pedes quatuor antici flavi. 
61. Fasricu. C. collo nigro, thorace rufo, elytris cinereo-rufoque striatis. 
Dytiscus varius. Fab. Syst. Eleuth. i. p. 267, 48. 
Long. corp. 3 
Oss. Fabricius described an insect in the Ent, Syst. which he found in the Banksian cabinet, 
and called it D. varius. Afterwards he confounded a Sumatra insect, which he found in Daldorff’s 
cabinet, with his D. varius, and altered the original specific character to suit his new insect, 
which I here call D. Fabricii. 
62. Sururais. C. elytris cinereo-nigroque variegatis: striis tribus punctorum impressis sutura nigra linedque 
utringue rubra. 
Long. corp. 4 
Caput obscure ferrugineum punctis duobus impressis medio utrinque nigrum, ore palpis antennisque 
testaceis. Thorax glaber levis marginatus subcanaliculatus rufus macula media transversali nigra. 
Elytra punctis numerosissimis approximatis nigris cinereisque variegatis, striis punctorum obsoletis, 
margine exteriore rubro. Corpus subtus nigrum, pedibus quatuor anticis femoribusque posticis piceis. 
63. Virrarus. 
