ICHNEUMON-FLIES, PART 2\ XORIDINAE 449 



the descriptions of females should be made, with some allowances for 

 sexual differences. 



Odontocolon is parasitic on Coleoptera in dead wood. Adults are 

 moderately common on herbage and underbrush, in forests where 

 there is fallen wood. They are frequently found at honeydew. 



Keys to the Nearctic species of Odontocolon 



MALES 



(Males of cilipes, depressum, alaskensis, and dreisbachi are unknown, but are 

 placed in the key according to the characters they are presumed to have.) 



1. Longitudinal ridge just distad of ventral tooth on hind femur convex in pro- 



file; hind tibia usually with some long hairs in addition to the short clothing 

 hairs (always with these hairs in the Nearctic species) ; intercubital vein 

 usually less than 0.4 as long as second abscissa of cubitus; thorax unusually 

 long and depressed, and with coarse punctures. Cilipes group (p. 454) . 2 

 Longitudinal ridge just distad of ventral tooth on hind femur straight or con- 

 cave in profile, or the ridge sometimes short or absent; hind tibia never 

 with long hairs in addition to the short clothing hairs; intercubital vein 

 usually more than 0.3 as long as second abscissa of cubitus 3 



2. Tooth on hind femur about 1.0 as high as its basal width, not separated by a 



distinct notch from the longitudinal ridge just distad of the tooth; inter- 

 cubitus about 0.4 as long as second abscissa of cubitus. 



1. cilipes, new species 

 Tooth on hind femur about 1.5 as high as its basal width, separated by a 

 rounded notch from the longitudinal ridge just distad of the tooth; inter- 

 cubitus less than 0.3 as long as second abscissa of cubitus. 



2. bicolor (Cresson) 



3. First tergite mostly or entirely covered with moderately coarse longitudinal 



striae; metapleurum entirely rugosopunctate; wings often reduced or vesti- 

 gial, when well developed often with a long ramellus. Polymorphtjm 



group (p. 456) 4 



First tergite mostly smooth, mat, or with a small or moderate amount of 

 longitudinal wrinkling or striae; metapleurum with rather weak punctures, 

 sometimes partly rugosopunctate, or rarely entirely so; wings fully de- 

 veloped; ramellus short or absent. Mellipes group (p. 458) 6 



4. Head about 1.18 as wide across temples as across eyes. 



5. formicoides, new species 

 Head 0.95 to 1.04 as wide across temples as across eyes . . 5 



5. Head and thorax blackish brown; basal 0.6 of second tergite with rather close, 



small punctures and a small amount of longitudinal striation. 



3. pullum, new species 



Head and thorax light brown; basal 0.6 of second tergite longitudinally striate 



and with some inconspicuous punctation . . 4. polymorphum Cushman 



6. Distal side of tooth on hind femur ending abruptly, not continued distally 



onto hind femur as a ridge; thorax about 2.8 as long as high. 



6. depressum, new species 



Distal side of tooth on hind femur ending gradually, continued on to adjacent 



part of femur as a sharp ridge; thorax less than 2.8 as long as high ... 7 



