158 M. W. R. de V. GRAHAM 



4 (3) Gastral petiole smooth or with only some very weak sculpture, subconical, as 



broad as or slightly broader than long. Antennal flagellum stout, distinctly 

 stouter than the pedicellus, hardly clavate, with all the funicular segments 

 (except sometimes the first) at least very slightly transverse. Maxillary 

 stipites large, reaching up to near the vertex ; last two segments of maxil- 

 lary palpi forming a moderately large sac which is about 1-5 times as long 

 as broad and subelliptical. Large species, 2-5 to 3 mm. hippeus (Walker) (p. 161) 



- Gastral petiole either wholly reticulate, or else about twice as broad as long ; 



usually with subparallel sides though this feature is not so obvious when the 

 petiole is strongly transverse. Antennal flagellum sometimes different in 

 form. Species sometimes smaller ....... 5 



5 (4) Maxillary palpi only slightly dilated apically, the sac formed by the two ter- 



minal segments elliptic and about three times as long as broad. Antennae 

 with proximal segments of funicle quadrate to slightly longer than broad, 

 distal segments hardly transverse. Maxillary stipites large. Antennae, and 

 legs except coxae, yellow. Gastral petiole as long as broad 



laevigata Thomson (p. 160) 



- Either the maxillary palpi are strongly dilated apically, with the sac formed 



by the two terminal segments subglobose ; or if the sac is more elongate and 

 elliptic, then the distal segments of the funicle are strongly transverse. 

 Maxillary stipites sometimes small. Gastral petiole often transverse . 6 



6 (5) Gastral petiole distinctly (up to 2-5 times) broader than long, distinctly 



shorter than the median length of the propodeum ..... 7 



- Gastral petiole quadrate to somewhat longer than broad, not or hardly 



shorter than the median length of the propodeum . . . . . 11 



7 (6) Maxillary stipites small, practically unmodified ; palpi not much swollen, the 



sac formed by the two terminal segments elliptic and slightly longer than 

 broad. Antennal scape, all femora, and sometimes the tibiae, more or less 

 infuscate. Small species, 1-3 to i-8 mm. . . poreia (Walker) (p. 162) 



- Maxillary stipites large, reaching up to near the vertex ; the sac formed by 



the two terminal segments of the palpi elliptic or subglobose. Species 

 usually larger (size i-8 to 3-5 mm.) ....... 8 



8 (7) Smaller species, i-8 to 2-2 mm. Sac formed by the two terminal segments 



of the maxillary palpi subglobose .... polita (Walker) (p. 162) 



- Usually larger (1 -8 to 3-5 mm.). Sac formed by the two terminal segments of 



the maxillary palpi 1-5 to 2 times as long as broad .... 9 



9 (8) Head in dorsal view with temples fully half as long as eyes, parallel for a short 



distance behind the eyes. Length about three mm. Sac formed by the two 

 terminal segments of the maxillary palpi about 1 -5 times as long as broad 

 (Amurland) ....... nobilis (Walker) (p. 161) 



- Head in dorsal view with temples one third as long as eyes or slightly less, 



converging slightly even just behind the eyes. Species either smaller, or else 

 with the sac formed by the two terminal segments of the maxillary palpi 

 relatively longer . . . . . . . . . . .10 



10 (9) Sac formed by the two terminal segments of the maxillary palpi about twice as 

 long as broad. Scutellar frenum marked off by a fine line. Length 2-5 to 

 3 mm. ....... brevicornis Thomson (p. 161) 



- Terminal sac of maxillary palpi somewhat less than twice as long as broad. 



Scutellar frenum marked off by a very distinctly impressed line. Length 

 hardly 2 mm. ....... mustela (Walker) (p. 161) 



n (6) Maxillary stipites large, reaching up to near vertex, and clearly visible when 

 the head is seen in dorsal view. Apex of basal cell of fore wing with a patch 



