6 PROCEEDINGS OF THE NATIONAL MUSEUM vol. i04 



26. Large (7-10.5 mm. in length) 27 



Smaller (5-7 mm. in length) 29 



27. Tarsal joints deep brown (Mexico) jaiopensis, new species (p. 32) 



Tarsal joints pale 28 



28. Elytral vittae moderately wide (Costa Rica) 



turrialhensisf new species (p. 38) 

 Elytral vittae narrow (Mexico, Central America, Colombia) 



quinquelineata (Latreille) (p. 31) 



29. Distinctly oval, prothorax short and broad (El Salvador) . ovata Blake (p. 35) 

 Oblong oval, prothorax not unusually short and broad 30 



30. Head entirely pale (Mexico, Guatemala, Honduras) 



guatemalensis Jacoby (p. 21) 

 Head with a dark spot on occiput 31 



31. Femora entirely dark, tibiae with pale band below base (Mexico) 



annulata, new species (p. 51) 



Femora with a dark streak only, tibiae entirely dark t (Mexico, Central 



America) fumata var. labiata Jacoby (p. 23) 



32. Antennae unusually long, extending well below humeri nearly to the middle 



of the elytra 33 



Antennae not unusually long, not extending much below humeri ... 34 



33. Explanate margin on prothorax and elytra wide, prothorax usually with a 



broad Y-shaped median marking and a spot on each side (Costa Rica, 



Panamd, Colombia) panamensis Jacoby (p. 41) 



Explanate margin not unusually wide, anterior pronotal spots rather closely 

 set and not in a broad Y-shaped formation (Mexico, Central America) 



fumata (LeConte) (p. 23) 



34. Margin of elytral vittae a deeper brown in color than rest of vittae (Mexico, 



British Honduras) brunneofasciata Jacoby (p. 36) 



Margin of elytral vittae uniform in color with rest of vittae 35 



35. Prothorax and elytra rather coarsely punctate, anterior pronotal spots small 



and not closely set (United States, Mexico) .... arizonae Casey (p. 19) 

 Prothorax and elytra not coarsely punctate, anterior pronotal spots not 

 very small and not widely separate 36 



36. Head dark on occiput (Pacific coast of Canada and United States, Baja 



California) latiovittata Hatch (p. 17) 



Head without darkening on occiput 37 



37. Anterior pronotal spots large and dark (Mexico) . knabi new species (p. 25) 

 Anterior pronotal spots pale and faint and not large (Mexico) 



gracilis, new species (p. 37) 



Key to the vittate species of Disonycha from South America 



1. Median elytral vitta with a pale inner line 2 



Median elytral vitta without a pale inner line 3 



2. Pale line in median elytral vitta usually only in apical half; prothorax usually 



with two dark spots close together anteriorly (Amazon River, Brazil) 



scissovittata, new species (p. 73) 

 Pale line in median elytral vitta extending most of the length of vitta; pro- 

 thorax with two anterior dark spots widely separated (Argentina, southern 

 Brazil) interlineata Berg (p. 72) 



3. Median elytral vitta represented only in part by spots or short lines either 



at base or near apex, sometimes also mediall}' 4 



Median elytral vitta or vittae entire 5 



