THE PEEBACEOUS DIVING BEETLES. 225 



KEY TO INDIANA SPECIES OF AGABtlS. 



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

 neath. 

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



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



436. ANTHBACINUS. 



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



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

 f1. Elytra brownish, more or less pale; inner margin of hind tibise 

 without punctures ; prosternal spine acutely carinate along the 

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



dd. 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. seeiatus. 



cc. Front tarsal claws of male simple or acutely dentate, 

 e. Front claws of male simple. 



/. Inner margin of hind tibiae without punctures, 

 fir. Prosternal spine rather narrow, convex. 



7i. Elytra dark reddish-brown, very shining, without a submar- 



ginal pale stripe, their surface not coarsely reticulate; 



length 7.5-8.5 mm. 439. pdngtatus. 



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



their surface coarsely and unequally reticulate; length 



8 mm. EETIOXJLATTJS. 



gg. 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. 



, /A Inner margin of hind tibise with a row of deep punctures ; thorax 



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



441. GAGATES. 



ee. Outer fi'ont claw of male acutely dentate near the base. 

 j. Elytra dull yellow with black stripes. 

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

 the next three combined ; length 9 mm. t.eniolatus. 



A/,'. Rleso- and metasterna and coxie black ; first joint of middle 

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

 jj. Elytra not dull yellow. 



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



iranctulate; length 7 mm. 44.3. ^neolus. 



U. Elytra black. 



m. Form broad, subdeprossed ; 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 iiunctures ; length (J-7 mm. 



445. SEMIPUNCTATUS. 



