On Aquatic Carnivorous Coleoptera or Dytisade. 511 
703. Agabus lineellus, Lec., M.C.—“ Regulariter ovalis, piceo-ferrugineus, nitidus 
subtilissime reticulatus, elytris testaceis, sutura et vittis utrinque quatuor angustis, 
nigris antice abbreviatis, nebulisque exterius piceis ornatis, sternis piceis.” Long. 
7a, lat. 4 m.m. . 
I have seen only a single very immature female that I can refer to this species, 
the reticulation of the elytra is much more distinct than itis in Colymbetes teniolatus, 
and the mesosternal groove is excessively indistinct being very narrow, and 
obliquely perpendicular in its direction, the prosternal process short, and with the 
sides much compressed. 
North America, (California). 763. 
704. Agabus lineatus, Gebl., M.C.—Ovalis, brevis et latiusculus, sat convexus, 
testaceus, pectore coxisque posterioribus obscuris; elytris subtiliter sed haud 
obsolete reticulatis, lineis 5 elongatis suturaque nigris. Long. 62, lat. 4 m.m. 
Of this species I have seen only a single immature female individual : it seems 
very closely allied to Agabus lineellus but is shorter, and the hind coxz are shorter ; 
the prosternal process and mesosternal grooves are similar except that the latter 
is more horizontal (less oblique). 
Siberia. 764. 
705. Dytiscus didymus, Ol., Agabus didymus, M.C.—Ovalis, sat convexus, sat 
nitidus, robustus, niger, supra zenescens, prothoracis lateribus elytrorumque epipleuris 
ferrugineis, elytris macula didyma pone medium versus latera, aliaque rotundata 
apicali pallidis, antennis testaceis, pedibus piceo-rufis; supra subleevigatus, elytris 
subsericantibus, obsoletissime punctulatis ; prothorace basi utrinque versus angulos 
posteriores leviter sinuato, his subrectis. Long. 8, lat. 4¢ m.m. 
The male has the front and middle tarsi distinctly incrassate, and furnished 
beneath with rather long hairs, bearing small palettes; the claws scarcely differ 
from those of the female. 
The species is very readily distinguished by the peculiar nale mark near the side 
of the elytra, which in clean specimens is always conspicuous, and is formed by 
two small spots nearly or altogether coalesced. 
Central and Southern Europe, and Algeria, (England, France, Germany, Spain, Tangier). 769. 
