538 On Aquatic Carnivorous Coleoptera or Dytiscide. 
758. Agabus regularis, Lec., M.C.—Ovalis, crassus, convexiusculus, piceus, supra 
eenescens, antennis rufis ; supra undique densius minus subtiliter reticulatus ; thorace 
cum elytris continuo, antrorsum angustato, margine laterali, lato, humili; elytris 
pone medium vittula parum conspicua testacea ; antennis sat elongatis et gracilibus ; 
pedibus posterioribus brevibus et crassis. Long. 11, lat. 6 m.m. 
The male has the three basal joints of the front and middle tarsi a good deal 
incrassate, and furnished beneath with moderately short hairs, many of which bear 
minute palettes. ‘There is no sexual difference of sculpture. 
The species is remarkable by its short, thick, hind legs ; their development, indeed 
for swimming organs is more advanced than in any species of Agabus. 
North America, (San Diego, California). 831. 
I. 48.—Genus PLATYNECTES. 
Side of prothorax with a raised margin ; hind coxe very large, so that the wings of 
the metasternum are greatly reduced, and are slender and linear : hind legs rather 
long and slender ; epipleurze behind the middle very narrow. 
The thirteen species * of this genus form three groups, viz :— 
Group 1.—Ventral segments strigose ; prosternal process not broad nor flat, but 
somewhat compressed and carinate along the middle. Male tarsi 
distinctly incrassate. Upper surface evidently reticulate. Species 
inhabiting Australia and Tasmania. Nos. 759 to 762. 
Group 2.—Ventral segments polished prosternal process rather broad, nearly 
flat, very acuminate. Species found in Australia and Asia. Nos. 
763 to 766. 
Group 3.—Upper surface very polished ; prosternal process broad, flat, but 
little acuminate. Species found in South America. Nos. 767 to 771. 
Group 1. 
759, Platynectes senescens, n. sp.—Ovalis, haud angustus, minus convexus, sat 
nitidus, supra crebre subtiliter reticulatus, niger, supra eenescens, prothorace ad 
latera vage angusteque ferrugineo, elytris macula sublaterali pone medium testacea, 
antennis pedibusque rufis, thorace cum elytris omnino continuo, angulis posterioribus 
haud acutis ; prosterni processu angusto. Long. 64, lat. 4 m.m. 
* In addition to these it is probable that the following names refer to species of this genus. Agabus 
bakewelli, Clark (No. 1181); Australia.—Agabus lugubris, Blanch. (No. 1195)? No. 763 var. ; Tasmania. 
-—Agabus tasmanie, Clark (No. 1203; near No. 764; Australia, Tasmania.—Colymbetes lineatus, Redt. 
(No. 1237)? near No. 766 ; India.—Colymbetes magellanicus, Bab. (No. 1238) ; Patagonia.—Colymbetes 
monostigma, Hope (No. 1240), gen. dub. ; Australia.—Colymbetes octodecim-maculatus, Macl. (No. 1242) ; 
Java.—Colymbetes submaculatus, Cast. (No. 1252) ; near No. 769 ; Cayenne. 
