546 U. S. NATIONAL MUSEUM BULLETIN 216 



4. Hind tarsal claws with a small, acute accessory tooth near the midlength; 



intercubital beyond second recurrent by 0.4 to 0.6 its length. 3. Arotes (p. 561) 



Hind tarsal claws without an accessory tooth; intercubital opposite second 



recurrent, or beyond it by as much as 0.15 its length . 4. Spilopteron (p. 568) 



1. Genus Coleocentrus 



Figure 308,a 



Coleocentrus Gravenhorst, 1829, Ichneumonologia europaea, vol. 3, p. 437. Type: 

 Ichneumon excitator Poda; designated by Westwood, 1839. 



Macrocoleus Desvignes, 1850, Trans. Ent. Soc. London, n. s., vol. 1, p. 13. Type: 

 (Macrus longiventris Gravenhorst) =excitator (Poda); designated by Viereck, 

 1914. 



The more important generic characters are stated in the key. 



The genus Coleocentrus is Holarctic. The species are characteristic 

 of cool moist woods of older trees. An exception to this distribution is 

 C. rufus, which is common in rather dry woods, and ranges south into 

 the Upper Austral zone. The hosts are almost certainly in dead 

 (probably decaying) wood, but there are no rearing records for 

 Nearctic species. 



There are eight Nearctic species, about half of which are rare in 

 collections. Morphologically the species of the genus are but poorly 

 differentiated. Aside from the absence of the areolet and prepectal 

 carina in C. flavipes, the Nearctic species are distinguished best on 

 color, the shape of the male clasper, and the distribution of hairs on 

 the face, clypeus, second tergite, and third sternite. 



Keys to the Nearctic species of Coleocentrus 



MALES 



1. Areolet absent; clasper as in figure 378 8. flavipes Provancher 



Areolet present 2 



2. Apex of clasper obliquely truncate (figs. 376 and 377) 3 



Apex of clasper rounded or squarely subtruncate 4 



3. Thorax black 6. mantii Cushman 



Thorax ferruginous 7. rufus Provancher 



4. Tegula black; clasper as in figure 373 3. pettiti Cresson 



Tegula yellow or pale fulvous 5 



5. Second through fourth segments of hind tarsus dark brown; apex of clasper 



truncate (fig. 374) 4. harringtoni Cushman 



Second through fourth segments of hind tarsus yellowish; apex of clasper 

 rounded 6 



6. Middle coxa yellowish; subbasal band of hairs on clypeus containing about 



15 hairs; clasper as in figure 375 5. rufocoxatus Pratt 



Middle coxa blackish to fulvous; subbasal band of hairs on clypeus containing 

 about 30 hairs; clasper as in figures 371 and 372 7 



7. Hind coxa black with fulvous stains, to black with the base infuscate; second 



tergite about 2.4 as long as wide; clasper a little longer than in C. quebecensis; 

 range: western part of Transition and Canadian zones. 



1. occidentalis Cresson 



