ICHNEUMON-FLIES — GELINAE : MESOSTENINI 99 



0.83 as long as front wing; ovipositor compressed, the teeth on its 

 lower valve as subvertical ridges, rather widely spaced. 



Aritranis is close to Gambrus, Caenocryptus , Idiostoma Cameron, 

 and Caenocryptoides. In Caenocryptoides the clypeus has a rather 

 strong preapical convexity (the convexity a little impressed medially), 

 the basal ridges of the ovipositor tip slant forward and upward, the 

 apical carina of the propodeum is obsolescent, and the petiole has a 

 blunt basolateral tooth. Otherwise it is rather like Aritranis. The 

 species of Caenocryptoides are eastern Palearctic. In Caenocryptus 

 the areolet is more or less pentagonal and always rather small, the 

 second recurrent vein arched outward from its attachment to the 

 areola, and the body punctures average w^eaker than in Aritranis. 

 It appears to be no more than a weakly differentiated offshoot of 

 Aritranis. The species of Caenocryptus are Palearctic. The dis- 

 tinction between Aritranis and Gambrus is more difficult. Both 

 genera may be polyphyletic, and though it seems unwise either to 

 synonymize them, or to subdivide on the obscure phyletic lines, no 

 really natural and satisfactory division between the two seems possible. 

 See the key to genera for the most useful differences. Among the 

 Nearctic species, A. qffabilis is of doubtful affinities. In most struc- 

 tural characters it is like Aritranis, but it has a definite basolateral 

 tooth on the petiole and the mesoscutum is mat as in Gambrus. Idio- 

 stoma is an Ethiopian genus, known only from the genotype, and not 

 available now for comparison. 



The sjmonymy of Hoplocryptus binotatulus Thomson, 1873, with 

 Cryptus jugitivus Gravenhorst, 1829, noted above in the generic 

 synonym}", is based on a comparison of Thomson's types with speci- 

 mens of Jugitimis from central Europe; but we have not studied 

 Gravenhorst's type. The type of Cryptus explorator Tschek, the geno- 

 type of Aritranis, is in Vienna. It represents a species close to the 

 Nearctic A. imitator. 



This genus is of Holarctic distribution, with nine species in the 

 Nearctic region and a larger number in Eurasia. Hosts are borers 

 in stems, twigs, or grass culms, or the nests of Aculeata in twigs, or 

 sawfly pupae in weed stems. Adults are usually collected among 

 low vegetation of all kinds, often in overgrown fields or along the edges 

 of woods. 



Key to the Nearctic species of Aritranis 



1. Hind coxa and trochanters black; apical transverse carina of propodeum evenly 

 arched or weakly sinuate; thorax short and stout; first tergite long. 



9. imitator (Provancher) 

 Hind coxa and trochanters ferruginous (rarely black in males of A. notata); 

 apical transverse carina of propodeum bowed forward in the middle, sin- 

 uate; first tergite shorter 2 



