On Aquatic Carnivorous Coleoptera or Dytiscide. 669 
A variety occurs in which the yellow vitta is indicated only in its basal and 
apical portions. 
Madagascar, Mauritius, Senegal, Caffraria. 1040. 
1046. Hydaticus rectangulus, n. sp.—-Ovalis, sat latus, nitidus, capite anterius 
testaceo, posterius nigro, thorace in medio nigro, ad latera late testacco, elytris 
nigris, vittis duabus latis integris, interiore a sutura parum distante, testaceis ; 
corpore subtus piceo, antennis pedibusque anterioribus testaceis, tibiis intermediis 
pedibusque posterioribus piceis ; elytris punctis seriatis minutis. Long. 123, lat. 
7% m.m. 
This species is of the form of Dytiscus vittatus (No. 1049), but is readily distin- 
guished from it by possessing two broad longitudinal bands on the wing-cases ; the 
inner of the two is separated from the suture only by one-fourth, or less, of the 
breadth of the wing-cases; moreover, at the base this yellow vitta has a small 
internal prolongation so that it nearly touches the scutellum. From Hydaticus 
bivittatus, the species is distinguished by its broader form, by the broader yellow 
stripes of the elytra, and by the shorter and thicker swimming legs, the hind mar- 
gins of the tarsal joints of which are moreover furnished with elongate cilize : also 
the external yellow band of the elytra, instead of continuing along the outer 
margin from the base to the apex, diverges from the outer margin a short distance 
behind the shoulder. A variety occurs in which the yellow bands are so broad as 
almost to be united into one large patch, the black vitta separating them being 
correspondingly diminished in size. Of the male I have seen only a single badly 
preserved individual, it appears not to differ in its tarsi from Dytiscus vittatus ; the 
female has no sexual sculpture, 
Persia, (Dr. Millingen) ; Northern India, (C. Boyd) ; (Kulu Kangra, Punjaub). 1041. 
1047. Hydaticus duplex, n. sp.—Oblongo-ovalis, sat latus, capite anterius testaceo, 
posterius nigro, thorace nigro, ad latera testaceo, elytris nigris, vittis duabus integris 
testaceis, vitta interna, a sutura sat distante, pone basin cum fascia transversa flava 
fere ad scutellum extensa, conjuncta; corpore subtus nigro-piceo, antennis pedibus- 
que anterioribus testaceis, tibiis intermediis piceis, pedibus posterioribus fere nigris, 
elytris punctis seriatis sat conspicuis. Long. 142, lat. 8 m.m. 
This species seems very closely allied to D. vittatus, but is rather larger than the 
longest individual of that species aud is more oblong in form: the external yellow 
vitta of the elytra is continued to the extremity of the wing-case, while the internal 
one is towards the apex approximated a little nearer to the suture than it is in D. 
vittatus, and moreover sends off near its commencement an internal prolongation 
4H 2 
