THE PBEDACEOUS DIVING BEETLES. 



225 



KEY TO INDIANA SPECIES OE AGABUS. 



• Outer front tarsal claw of male elongate and dilated or thickened be- 

 neath. 



6. Elytra brownish-yellow; length 9.5 mm. erythropterus. 

 1)1). Elytra black, finely and densely reticulate ; length 6.5-7.5 mm. 



436. ANTHRACINUS. 



. Outer front claw of moderate length, not dilated beneath. 

 c. Front tarsal claws of male compressed, obtusely dentate at base. 



d. Elytra brownish, more or less pale; inner margin of hind tibiae 



without punctures; prosternal spine acutely carinate along the 

 middle ; length 8.5-9.5 mm. 437. confinis. 



del. Elytra black or brassy black; inner margin of hind tibiae with a 

 row of punctures ; prosternal spine broad, nearly flat ; length 9- 

 10 mm - 438. SERIATUS. 



ee. Front tarsal claws of male simple or acutely dentate. 



e. Front claws of male simple. 



/. Inner margin of hind tibiae without punctures. 

 g. Prosternal spine rather narrow, convex. 



h. Elytra dark reddish-brown, very shining, without a submar- 



ginal pale stripe, their surface not coarsely reticulate; 

 length 7.5-8.5 mm. 439. punctattts! 



hit. Elytra fuscous with a reddish-yellow submarginal stripe; 

 their surface coarsely and unequally reticulate; length 



8 mm - RETICULATUS. 



00. Prosternal spine broad, flat, polished; elytra black, each with 

 a dull yellow submarginal stripe. 



i. Broadly ovate ; under surface reddish-brown; length 10 mm. 



440. STAGNINUS. 



ii, More narrowly ovate ; under surface black ; length 7.5-8 mm. 



OBTUSATUS. 



//'. Inner margin of hind tibiae with a row of deep punctures; thorax 

 finely margined ; elytra uniform piceous, shining ; length 9 mm. 



441. GAGATES. 



ee. Outer front claw of male acutely dentate near the base. 

 j. Elytra dull yellow with black stripes. 

 k. Body beneath wholly red; first joint of middle tarsi equal to 

 the next three combined ; length 9 mm. tjeniolatus. 

 II: Meso- and metasterna and coxae black; first joint of middle 

 tarsi less elongate ; length 7.5-8 mm. 442. disintegrate. 

 j). Elytra not dull yellow. 



I Elytra reddish-piceous with a greenish or brassy tinge, finely 

 punctulate ; length 7 mm. 443. ^ NEOLUS 



11. Elytra black. 



m. Form broad, subdepressed ; elytra with a subapical pale 

 stripe; length 8.5-9 mm. 444. semivittatus. 



mm. Form narrow, convex; elytra without pale stripe but with 

 numerous irregular punctures ; length 6-7 mm. 



445. semipunctatus. 



