240 BRITISH ICHNEUMONS. [Stiipnides 



I have seen a specimen taken at Charing in Kent (probably in moss), by 

 Chitty, on the 20th May, 1905. 



TRIRK. 



STILPNIDES. 



This Group is of but small extent and the sexes differ considerably in 

 facies. The females are easily distinguished from the remainder of the 

 Cryptinae by their either orbicular and extremely deplanate, or very 

 strongly convex and apically compressed abdomen, and not or very shortly 

 exserted ovipositor. The males for the most part resemble those of 

 Phygadeuon and Hemiteles ; the abdomen is, however, more strongly 

 nitidulous and the areolet is smaller, rarely externally entire, emitting the 

 external cubital nervure from the centre, that is to say, higher than is 

 usual in those genera. Both sexes are, nevertheless, abundantly distinct 

 in having the metathorax declived from base to apex with no trace of a 

 central transverse costa, but always bearing a longitudinal dorsal channel 

 composed of the confluent central and petiolar areae ; the coxae are said 

 to be usually inserted a little before the apex of the metathorax, but I fail 

 to follow this distinction very clearly. 



Considerable doubt has been expressed regarding the position of these 

 genera. Gravenhorst placed Atractodes among the Opiiioninae on account 

 of the compressed female abdomen, and Exolytiis in the Tryphonifiae, 

 considering Siilptms to belong to the Ic/iJieiunojiifiae, because its terebra 

 was not distinctly exserted. Taschenberg included Stilpniis and Exolytus^ 

 but not Atractodes, in the Cryptinae, where the first alone was treated of 

 by Marshall, who left the latter two, as placed by Holmgren, in the Ophio- 

 ninae. These three genera were exhaustively monographed by Forster, 

 in 1876, who, amid great chaos, at least showed conclusively their close 

 relationship. He was followed by Thomson, who admirably treated of 

 them in his great Opusc. Ent., but failed to discover valid distinctions 

 between Exolytus and Atractodes ; and none of the Continental authors 

 have given adequate attention to Haliday's succinct descriptions of sixteen 

 species of the latter genus " indicated in Mr. Curtis's Guide." One of his 

 species appears so incongruous in any of the above genera, that I have 

 thought it advisable to erect a new one for its reception. 



Table of Genera. 



Apophyses usually stout ; areolet entire ; $ 



abdomen ovate .Stilpnus, Grav. 



Apophyses wanting ; areolet not entire ; 

 abdomen elongate, of $ compressed. 



Labial palpi with apical joint normal ; 

 petiolar spiracles behind centre. 



Head transverse ; metathorax rarely pro- 

 duced ; basal segment curved ATRACTODES, Grav. 



Head cubical ; metathorax produced ; basal 



segment straight Exolytus, Hot/ngr. 



Labial palpi with apical joint elongate ; 



petiolar spiracles central Mes.\tractodes, Mori. 



