320 



Leech and Chandler: Coleoptera 



10 



11 



12 



13 



Outline of pronotum and elytra not or very slightly 

 discontinuous, pronotum not constricted basally, at 

 most but slightly narrower than elytral base 4 



. Row of punctures paralleling lower posterior margin 

 of hind tibiae closely set, forming an almost continuous 

 groove from near base almost to apex, or with a less 

 regular double row; metasternal wings narrow (fig. 



13:176) 5 



Lower posterior margin of hind tibiae without a row 

 of punctures paralleling margin, or with a single row 

 of distinctly separated punctures; metasternal wings 

 broad (fig. 13:17c) or narrow 9 



. Outer 3rd of metasternal wings narrow, tonguelike, 

 nearly parallel-sided, apically sinuate, about as wide 

 as an epipleuron adjacent to 2nd abdominal sternite 



(fig. 13:176) 6 



Outer 3rd of metasternal wing more nearly triangular, 

 straighter, all but apex much wider than an epipleuron 

 adjacent to 2nd sternite (fig. 13: 17a) 7 



, Many meshes of elytral reticulation in basal half of 

 disc joined end to end, forming irregular series, but 

 those at sides and apex discrete as usual; a notably 

 convex species, hind tibiae short and broad, elytra 

 usually with a brassy tinge (fig. 13:160"); California. 



regularis (LeConte) 1852 



Meshes of elytral reticulation often lightly impressed 

 on disc, but of same type throughout; flatter species, 

 elytra black; San Francisco Bay area south to Monterey 



region brevicollis LeConte 1 857 



Hind femora strongly obliquely strigate; inner claws 

 of front tarsi of male with small basal tooth; elytral 

 sculpture of female like that of male, or with meshes 

 very elongate and narrow, strongly oblique, the surface 



opaque; northern North America, Siberia 



tristis Aube 1838 



Hind femora punctate; claws not toothed 8 



Hind femora and trochanters usually with coarse 

 punctures, carination of presternum continued along 

 prosternal process; form narrower, more convex, elytral 

 sculpture deeply impressed; Mendocino County (com- 

 mon), south to Tulare and Los Angeles counties (rare) 



ilybiiformis (Zimmermann) 1928 



Hind femora and trochanters very finely punctate, 

 prosternal process broader and almost flat; elytral 

 sculpture lightly impressed; San Francisco Bay north- 

 ward pandurus Leech 1942 



Prosternal process rather broad, sharply acuminate, 

 only moderately convex; hind tibiae with full row of 



punctures paralleling lower posterior margin 10 



Prosternal process narrower, varying from moderately 



convex to angularly or acutely carinate 11 



Metasternal wings narrower (fig. 13:17c), least dis- 

 tance from middle coxae to hind coxal plates less 

 than 1/2 width of the latter, measured along the same 

 line; more elongate, subparallel, rather flat species, 

 elytral reticulation lightly impressed; western U.S. 



and Canada seriatus intersectus (Crotch) 1873 



Metasternal wings broader, least distance from middle 

 coxae to hind coxal plates more than 1/2 the width 

 of the latter; oval, broader, more convex species, 

 elytral reticulation more deeply impressed; western 



North America lugens LeConte 1852 



Hind tibiae with a row of punctures paralleling lower 



posterior margin 12 



Hind tibiae without such a row of punctures, or with 



only a few punctures near base or in basal half 15 



Individual meshes of elytral reticulation greatly 

 elongated; larger species, 10-11 mm. long; Pacific 



Coast discors LeConte 1861 



Elytral meshes more or less quadrate 13 



Pronotum sharply but very narrowly margined at sides; 

 smaller species, 7 mm. long; California to Oregon 



vandykei Leech 1942 



Pronotal margin almost as broad as a median antennal 

 segment, rather flat; larger species, 8-10 mm. long 

 14 



14. Hind angles of pronotum nearly rectangular; last 

 abdominal sternite of male with strigosities at each 

 side of middle at an angle to median line of the insect, 



and more numerous; Pacific Coast 



walsinghami (Crotch) 1873 



— Hind angles of pronotum obviously obtuse; strigosities 

 of last male sternite nearly parallel with long axis 

 of body, less numerous; Pacific Coast 



confertus LeConte 1861 



— Hind angles of pronotum less than a right angle; 

 prosternal process elongate, sharply acuminate, on 

 same plane as presternum; hind femora coarsely punc- 

 tate (see ilybiiformis, couplet 8) 



15. Elytral reticulation coarse in both sexes, the in- 

 dividual meshes often about as wide as is a median 

 antennal segment 16 



— Elytra finely or minutely reticulate in the male, more 

 coarsely so in the female 17 



16. Reddish-brown, metasternum and hind coxal plates 

 blackish; prosternal process glabrous; larger, more 

 robust species, 8.5-9.0 mm. long; Pacific Coast 



austini Sharp 1882 



— Black, elytra brownish or fuscous; prosternal process 

 finely pubescent; smaller nearly parallel-sided species, 



6.75-8.3 mm. long; Pacific Coast 



strigulosus (Crotch) 1873 



17. Front tarsi of male broadly dilated, inner claws with 

 a median or subapical tooth 18 



— Front tarsi of male moderately or narrowly dilated, 

 inner (anterior) claws not toothed 19 



Fig. 13:17. Dytiscidae, adult structures of Agabus. a, pandurus, 

 metasternal wing; b, brevicollis, metasternal wing; c, seriatus 

 intersectus, metasternal wing; d, lutosus, apical segment and 

 claw of front tarsus of male; e, griseipennis, apical segment and 

 claw of front tarsus of male; f, ancillus, aedeagus; g, obsofefus, 

 aedeagus; h, morosus, aedeagus (Leech, 1942). 



