590 William T. M. Forbes 



Sc and R strongly anastomosing beyond the cell; female frenulum multiple, cell 

 open, M 2 most often stalked, sometimes lost; a heavy fringe of simple bristles 

 along base of Cu. Wings always smooth-scaled. Larvae and pupae of two radi- 

 cally different types, as described under Crambus and Diatraea. 

 The subfamily is fairly homogeneous. 



Key to the genera 



1. Fore wing with all radials preserved; "R x sometimes very short and becom- 

 ing coincident with Sc. 



2. R 2 _ stalked 64. Eoreuma. 



2. R 3 _ 5 stalked. 



3. Male antennae uni- or bipectinate 68. Thaumatopsis. 



3. Male antennas laminate, simple 69. Crambus. 



2. R 3 and R 4 only stalked. 



3. Rj becoming coincident, or anastomosing, or connected by a crossvein 

 with Sc. 

 4. Palpi twice as long as head; front more or less conical. .. .66. Argyria. 

 4. Palpi much longer. 



5. Ocelli present 67. Haimbachia. 



5. Ocelli absent 62. Diatraea. 



3. R, free. 



4. Ocelli absent 62. Diatraea. 



4. Ocelli present. 



5. Front conical : 63. Chilo. 



5. Front rounded. 



6. Palpus projecting its length beyond head 66. Argyria. 



6. Palpus projecting twice its length beyond head 65. Platytes. 



1. Fore wing with two radials and a median lost 70. Raphiptera. 



62. DIATRJEA Guilding 



Palpi beaklike, extending two or three times the length of the head; antennae 

 nearly simple, ocelli absent. Front usually conical. Body normally rather stout. 

 Fore wing moderately broad; R x typically becoming coincident with Sc; R 3 and R 4 

 stalked; the rest free. Hind wing somewhat broader, with Sc and R rather 

 strongly anastomosed; subcostal cell narrow, normal; Mj from upper angle of 

 discal cell, and M 2 and M 3 connate. 



Caterpillars, so far as known, borers in Gramineae, and most commonly in wet 

 places, slender, with strong tubercles; prolegs with an ellipse of triordinal hooks; 

 vii with two setae on meso- and metathorax, as in the Galleriinse; setae iv and v 

 of abdomen obliquely placed, i and ill of ninth segment of abdomen approximate, 

 and ii of eighth and ninth segments forming single dorsal plates. Pupa usually 

 cylindrical, truncate at anterior end; tongue short. 



The first group is ancestral to both Chilo and Diatraea, and the species have 

 been variously treated in the past. 



Key to the species 



1. Wings narrower; fold with alternating pale and dark shades. 



2. Hind wing white 2. forbesellus. 



2. Hind wing clay-color or brown 1. comptulalis. 



1. Wings broader; fold evenly colored or streaked longitudinally. 



2. Fore wing mouse gray, with traces of postmedial dots or immaculate. 



3. idalis. 



