344 NEOTROPICAL PSELAPHIDAE 



articulated deeply into the oblique apex of second, between the two lobes and 

 bears a single, very large, arcuate and shaip claw. 



From this resume it will be seen that Arhytodini offer affinities with 

 Ctenistini in pubescence, and Clavigerinae in oral structure, but have unique 

 tarsi. 



I have expanded and modified the 1909 key of Raffray to include later 

 species : 



ARHYTODES (Reitter 1881) 

 Reitter (1881) 

 Raffray (1890, 1891, 1904, 1909) 



The genus is sufficiently summarized above. The species may be separated 

 as follows: 



Dorsal striae of elytra entire ; disc of pronotum more or less longitudi- 

 nally elevated into a subcarinoid tumidity 2 



Dorsal elytral striae either absent, or if present not beyond the middle 

 of elytral length 7 



2. Antennomeres II, III, IV, V, and VII transverse; VI and VIII elon- 



gate; 2.7 mm. long; Argentina myrmecophilus 



Antennae not as above 3 



3. Antennomere III quadrate, as wide as long 4 



Antennomere III elongate, longer than wide 5 



4. IV three times longer than wide; V quadrate; VI three times longer 



than wide ; VII quadrate ; VIII three times longer than wide ; Brazil ; 



1.9 mm. long oberthuri 



IV-XI all longer than wide achillei new species 



5. IV transverse ; V-XI elongate ; Brazil brevicornis 



IV longer than wide 6 



6. All antennomeres cylindrical; dorsal elytral stria geminate or paired 



only at base ; Brazil ; 2 mm. long vestitus 



VIII, IX, and X obconical; dorsal elytral stria geminate for the entire 

 elytral length ; Brazil gounellei 



7. Elytra with dorsal striae , 8 



Elytra with no dorsal striae; pronotum with disc simply convex, not 



longitudinally gibbous; tergites not medianly gibbous; antennae 

 very long, nearly as long as body: I large and cylindrical; II quad- 

 rate; III, IV, V, and VII slightly, VI and VIII twice as long, as wide; 

 Argentina bruchi 



8. Dorsal elytral stria geminate and extending for half the elytral 



length; antennomere II quadrate; III-VIII about twice as long as 

 wide ; IX and X three times as long as wide ; tergites weakly gibbous 

 medianly ; pronotal disc strongly longitudinally carinoid ; Brazil . . . 



semisulcatus 



Dorsal elytral stria very short, not extending to middle of disc 9 



