On Aquatic Curnivorous Coleoptera or Dytiscide. 413 
joint. The mesosternal fork is not connected with the intercoxal process of the 
metasternum. 
The species* are Australian and Tasmanian. 
It should be noted that the Australian and Tasmanian genus Sternopiscus 
likewise has the front tarsi evidently five-jointed, but it has a very different structure 
of the mesosternum, (see p. 384). 
436. Hydroporus penicillatus, Clk., M.C.—(Species pervariabilis)—Brevissime 
pubescens, supra et infra densissime subtiliter punctatus, subopacus ; elytris 
seepius longitudinaliter carinatis, sed. interdum omnino equalibus; tarsorum 
anticorum articulo tertio brevi. Long. 4, lat. 24 m.m. 
The male is usually rather larger than the female, and has the front and middle 
tarsi moderately dilated, the front tibize are slender, and have a slight but distinct 
notch in the middle of the inner edge, the middle tibize are a little curved. The 
species is excessively variable, in colour, sculpture, and even in outline. Jndividuals 
from Tasmania are black, with the head yellow, and the sides of the thorax and 
the outer margins of the elytra also of that colour, the legs and antenne are also 
yellow with the outer portion of the latter infuscate : these dark individuals have 
an acutely elevated carina on the middle of the elytra. Individuals from West 
Australia present the other extreme ; they are entirely pale yellow, with the base 
of the thorax and some lines on the eiytra black, and there is no trace in some of 
these individuals of any unevenness on the elytra. Intermediate specimens in all 
these points are found, the variations being apparently rather constant in each 
locality. The male characters do not vary much, but the Tasmanian individuals 
of that sex have the front tarsi broader than those from Swan River. The female 
always has the front tarsi rather broad; each of the three basal jomts being as 
broad as, or rather broader than long. 
Tasmania, and Australia. 430. 
437. Hydroporus darwinii, Bab., M.C.—Ovalis, omnium densissime brevissimeque 
pubescens, densissimeque punctatus, opacus, sordide rufus, prothorace basi 
elytrisque signaturis confluentibus nigris; corpore subtus densissime punctato, 
omnino opaco: tarsorum anticorum articulo tertio elongato, basi tenui. Long. 4s, 
lat. 23 m.m. 
The male has the anterior and middle tarsi moderately broad; the front tibice 
are moderately broad, and have a deep notch on the middle of their inner edge, 
*Tn addition to those of which the characters are now given, the following also belong to the genus: 
Necterosoma flavicolle, Macl. (No. 1496),?=No. 441; Australia.—Necterosoma vittipenne, Macl. (Ne, 
1497),?= No. 436; Australia. 
3 H2 
