ICHNEUMON-FLIES, PART 2 1 XORIDINAE 491 



peared at first to be very distinct have proved to be joined to other 

 groups by species with intermediate characters (if not also relation- 

 ships) that one wonders about the durability of the groupings that 

 still seem usable. There is also the question whether it is worth- 

 while to distinguish those groups that happen to have characters 

 useful for a definition, but suppress those that may be otherwise just 

 as distinct but harder to define. Such taxonomic questions arise 

 frequently, but in the case of Xorides they are unusually hard to 

 answer. 



Key to the subgenera of Xorides 



1. Nervulus basad of basal vein; intercubitus basad of second recurrent by not 



more than its length; Old World species 2 



Nervulus distad of basal vein; intercubitus basad of second recurrent by more 

 than its length (or the intercubitus obliterated by the touching of radial and 

 cubital veins) 6 



2. Posterior transverse carina of mesosternum complete and strong; subapical 



bend of female flagellum involving two or three joints; second segment of hind 

 trochanter, as seen from the front side, about 2.5 as long as first segment. 



Palaearctic and Oriental 1. Gonophonus (p. 494) 



Posterior transverse carina of mesosternum broadly interrupted in front of each 

 middle coxa; subapical bend of female flagellum a sharp angle at a single 

 joint 3 



3. Prepectal carina present; Oriental and Australian species 4 



Prepectal carina absent; Ethiopian species 5 



4. Second segment of trochanter of front and middle legs without a tooth at apex 



on front side 2. Cyanoxorides (p. 494) 



Second segment of trochanter of front and middle legs with a tooth at apex on 

 front side 3. Epixorides (p. 494) 



5. Propodeum with apical transverse carina and median longitudinal carinae more 



or less distinct; notaulus more or less distinct . 4. Gonioprymnus (p. 495) 

 Propodeum without carinae; notaulus not distinct ... 5. Moansa (p. 495) 



6. Second trochanter of front leg with an acute apical tooth on the front side . . 7 

 Second trochanter of front leg without a distinct tooth 8 



7. Median lobe of mesoscutum without a median longitudinal groove; temple 



without striae, or with some weak oblique striae; second trochanter of 

 middle leg with an acute apical tooth on front side. Palaearctic. 



6. Moerophora (p. 495) 



Median lobe of mesoscutum with a broad, median longitudinal groove; temple 



with strong, mostly longitudinal striae (fig. 315,h); second trochanter of 



middle leg without a tooth. Nearctic 7. Exomus (p. 496) 



8. Second trochanter of hind leg, as seen from in front, about 2.5 as long as first 



trochanter; basal half of female flagellum wdth large, suberect hairs. Neo- 



tropic 8. Periceros (p. 501) 



Second trochanter of hind leg, as seen from in front, about 1.5 as long as first 

 trochanter; basal half of female flagellum with small, appressed hairs ... 9 



9. Scutellum without a subapical conical elevation; propodeum without a lateral 



subapical tubercle. Mostly Holarctic, but some species in Old World 



tropics 9. Xorides (p. 501) 



Scutellum with a subapical conical elevation; propodeum with a strong, lateral 

 subapical tubercle. Neotropic 10. Pyramirhyssa p. 530) 



