BEETLES OF THE GENUS MYOCHROUS — BLAKE 13 



9. Thorax with a thickened anterior margin, the scales on elytra form- 

 ing either short vittae or pale spots or band from the humerus 



down toward the suture 10 



Thorax usually not with a thickened anterior margin ; elytra with 

 no definite pale spotting or banding 12 



10. Thorax as long as wide, with a white median stripe, and elytra 



with a long incurving band from humerus toward suture and a 

 band before the apex not reaching the suture ; aedeagus with a 



broadly pointed tip (Colombia) darlingtoni, new species 



Thorax wider than long, almost as wide as elytra 11 



11. Elytra reddish brown with the scales forming a spot below basal 



callosity in the center, sometimes connected with the pale spot on 

 humerus, another in line with this before the apex and sometimes 

 another on the side ; aedeagus broad with very little trace of an 



acute tip at apex (Bolivia) bolivianus, new species 



Elytra black with the white scales forming vittate or semivittate 

 markings (Chaco Province, Argentina) chacoensis, new species 



12. Aedeagus with a liollowed-out scooplike tip 13 



Aedeagus not with a scooplike tip 14 



13. Scales not so dense as to conceal punctation (Panama, Colombia). 



platylonchus, new species 

 Scales denser, concealing punctation ; tip of aedeagus not quite so 

 broad (Ecuador, Peru) geminus, new species 



14. Aedeagus with a long drawn-out tip 15 



Aedeagus not with an unusually long drawn-out tip 19 



15. Deep reddish brown, thorax approximately as long as wide with 



small inconspicuous lateral teeth 16 



Piceous, thorax not as long as wide, with the usual well-developed 

 teeth 17 



16. Large, 6.5 to 7 mm. (Salta, Jujuy, Argentina) monrosi, new species 



Smaller, 5 mm. ("Pampas," Argentina) stenomorphus, new species 



17. Large, 6 to 7 mm., tip of aedeagus very long drawn out (Brazil, 



Uruguay, Argentina, Chile) armatus Baly 



Smaller, 5.5 to 6.5 mm., tip of aedeagus not so long drawn out 18 



18. Thorax approximately as wide as elytra (Trinidad) bryanti, new species 



Thorax not so wide as elytra (Paraguay) sapucayensis, new species 



19. Length 4 to 5 mm 20 



Length 5 to 6 mm 22 



20. Aedeagus pale with a dark furrow down tip (Panama, Colombia). 



elachius, new species 

 Aedeagus without a dai'k furrow down tip 21 



21. Elytra sparsely striate-punctate (Bolivia, Paraguay) nanus, new species 



Elytra with usual rather dense striate punctation (British, French, 



and Dutch Guiana, Venezuela, Brazil) paulus, new species 



22. Upper surface covered by unusually wide scales (Colombia). 



latisetiger, new species 

 Upper surface not covered by unusually wide scales 23 



23. Reddish brown ; aedeagus tipped with a fine point at apex 24 



Piceous ; aedeagus tipped with a broad point at apex 26 



24. Covered by grayish or pale brownish scales, the reddish-brown color 



not showing through ; thorax much wider than long, finely i>uno- 



tate (Colombia, Peru, Venezuela, Brazil, Bolivia) longipes, new species 



Covered by short yellowish scales, the reddish-brown color showing 

 through 25 



