190 ADEPHAGA. [A'/alttS. 



and thorax lighter, besides the usual 

 reddish spots ou vertex of head. 



A. Form larger, longer, and more de- 

 pressed ; legs ferruginous, femora 



dark A. CHALCOXOTUS, Panz. 



B. Form smaller, narrower, and more 

 convex ; legs clear red or testaceous; 

 male shining, female (var.) very 



dull A. TTLIGINOSUS, L. 



6. Upper surface dark with margins 

 broadly red, finely but plainly reticu- 

 late and dull. 



A. Form broad, oval A. Sttjrmii, Schijn. 



B. Form narrow, oblong A. aecticus, Pai/k. 



7. Thorax dark ; elytra brownish yellow 

 or reddish, passing from a lighter to a 

 darker shade, but with no distinct 



markings. 



A. Upper surface very shiny ... A. palttdostts, F. 



B. Upper surface rather dull ... A. congener, Thtmb. 



Tlie species are arranged below ■under their several groups as given 

 by Dr. Sharp ; there are no British representatives of the groups that 

 are omitted. 



Group II. 



Outline of elytra and thorax either continuous or but slightly dis- 

 continuous ; prosternal process comparatively broad, nearly flat, evenly and 

 di.^tiuctly margined, shining and impunctate ; wings of metasternum 

 large ; sexual differences of sculpture, as a rule, very slight ; male fore 

 feet but little developed. 



A. g-uttatus, Payk. Oblong oval, bronze-black, shining, rather 

 depressed ; labrum, two spots on vertex of head, antennae, and palpi red ; 

 thorax with sides strongly margined, a little broader at base than apex, pos- 

 terior angles right angles ; elytra somewhat parallel-sided, rugose towards 

 apex, smoother and more shining towards base, with two more or less dis- 

 tinct testaceous spots on each, one behind middle and one at apex ; legs 

 varying in colour, sometimes clear red, sometimes more or less piceous ; 

 elytra of female near base finely but distinctly reticulate ; in the male 

 the reticulation is less distinct, and the surface near base almost appears 

 finely and closely punctured. Long. 8, lat. 4 mm. 



Ponds, &c. ; generally in clear water with streams running through it; not un- 

 common and widely distributed throughout England and Wales, although somewhat 

 local ; Scotland, abundant both Lowlands and Highlands ; Irelaud, Armagh. 



A. big'uttatus, 01. (fontinalis, Steph., nitidiis, Steph.). Oblong oval, 

 shining black, rather depressed ; head with two spots on vertex usually 

 red ; antennas red with the apex as a rule black, paljDi piceous ; thorax 

 with base sinuate, sides somewhat contracted in front, lateral margins 

 not strong ; elytra with two testaceous spots on each, one behind middle, 

 the other at apex, both small and inconspicuous, the latter often obso- 

 lete ; female less shining than male ; the reticulation, however, varies 



