ICHNEUMON-FLIES, PART 2 1 EPHIALTINAE 219 



sen has published a rather complete account of several of them, as 

 well as of the biology of Tromatobia, Zaglyptus, and Clistopyga. (See 

 Entomologiske Meddelelser, vol. 14, pp. 137-205 (1923); vol. 16, pp. 

 152-155 (1928); vol. 16, pp. 366-368 (1929); vol. 19, pp. 192-215 

 (1935); vol. 20, pp. 25-28 (1937).) 



The generic classification of the tribe has taken form very slowly 

 because the representation of species in most collections is scanty, 

 and generic limits are often rather obscure. We have redefined the 

 genera of our fauna, erected some new ones, and added notes on some 

 of the extra-limital species that belong to these redefined or new 

 genera. Some of the genera are of problematic validity, but their 

 status cannot be exactly determined until a larger percentage of 

 the world fauna is known. 



Key to the Nearctic genera of Polysphinctini 



1. Areolet present (fig. 292,b); eye sparsely hairy in male, more densely hairy in 



female 1. Laufeia (p. 220) 



Areolet absent (figs. 293-297); eye not obviously hairy except in Schizopyga 

 and Zabrachypus 2 



2. Clypeus not separated from face (fig. 293, a); upper end of prepectal carina 



near front edge of mesopleurum; mandible with a broad thin flange inter- 

 nally; eye hairy 2. Schizopyga (p. 224) 



Clypeus separated from face by a groove (figs. 293,b-297,b) ; upper end of 

 prepectal carina distant from front edge of mesopleurum (figs. 293,b-297,b) , 

 mandible without a flange internally 3 



3. Median lobe of mesoscutum with a sharp vertical carina anteriorly on each 



side (fig. 294,a) 4. Acrodactyla (p. 230) 



Median lobe of mesoscutum without a vertical carina anteriorly on each 

 side 4 



4. Second through fourth tergites without grooves or swellings (fig. 295,a), 



evenly convex; notaulus absent; mesoscutum strongly mat and densely 



hairy 6. Piogaster (p. 241) 



Second through fourth tergites with oblique or transverse grooves, or with 

 paired median swellings; notaulus strong, though usually not sharp ... 5 



5. Discoidella completely absent and mesoscutum with hairs all over. 



10. Sinarachna (p. 258) 

 Discoidella present and/or mesoscutum hairless or partly hairless ... 6 



6. Third and fourth tergites each with a median pair of large rounded swellings 



(figs. 295,b-296,b) ; ovipositor sheath usually 3 to 4 times as long as apical 



depth of abdomen, or shorter in Oxyrrhexis (figs. 295,b-296,b) 7 



Third and fourth tergites with oblique grooves which delimit a central 

 rhombic area, or with transverse impressions (figs. 293,b; 294,b; 297,b); 

 ovipositor sheath 1 or 2 times as long as apical depth of abdomen (figs. 

 293,b; 294,b; 297,b) 9 



7. Epomia absent (fig. 296,b) ; temple flat, concave, or sometimes weakly convex; 



ocelli usually very large 9. Acrotaphus (p. 256) 



Epomia present (figs. 295,b; 296,a); temple convex, rarely flat; ocelli of 

 normal size 8 



