ICHNEUMON-FLIES — GELINAE : MESOSTENINI 523 



round or elliptic; front tibia of female not inflated; fourth tarsal 

 segment of female with a few weak bristles at apex, not bilobed; 

 areolet absent, not even a trace left of the second intercubital vein; 

 first intercubitus sometimes (in Latihulus) distad of second recurrent 

 vein; first tergite parallel-sided or more or less expanded apically, its 

 spiracle somewhat behind the middle; a pair of dorsal impressions 

 present on each of tergites 2-6 except m Sphecophaga; ovipositor 

 short, not surpassing tip of abdomen, its apex depressed or compressed, 

 the dorsal valve sometimes with obliquely transverse ridges; female 

 subgenital plate large, rhomboidal, weakly convex, reaching about 

 to apex of ovipositor. 



This subtribe is parasitic in the paper nests of social Vespidae. 

 There are only three genera, of which one is Nearctic. The other 

 two are Latihulus (Palearctic and Oriental) and Arthula (Oriental and 

 Australian). 



Genus Sphecophaga 



Figure 326,b 



Sphecophaga Westwood, 1840, Introduction to the modern classification of 



insects, vol. 2, synopsis of the genera . . . , p. 57. Type: Anomalonvesparum 



Curtis; original designation. 

 Chyronomon Desvignes, 1856, Catalogue of the British Ichneumonidae . . . British 



Museum, p. 47. Type: Anomalon vesparum Curtis; monobasic. 

 Cacotropa Foerster, 1868, Verh. Naturh. Rheinlande, vol. 25, p. 208. Type: 



(Cacotropa sericea Thomson) = vesparum (Curtis); included by Thomson, 



1888. 



Front wing 4.0 to 6.5 mm. long (or sometimes vestigial); body short 

 and stout; propodeum with some strong longitudinal wi'inkles that 

 appear like longitudinal carinae; intercubitus rather long, basad of 

 second recurrent vein; tergites 2-5 without impressions. 



Sphecophaga has only one species, which is Holarctic. It is a 

 moderately common parasite in Vespula nests. 



1. Sphecophaga vesparum (Curtis) 



Front wing 4.0 to 6.5 mm. long in specimens with fully developed 

 wings, shorter in brachypterous specimens. General structural fea- 

 tures as described under the generic heading and illustrated in figure 

 326,b. Color as described under the subspecies and forms. 



This species has two very distinct forms, which in Europe have 

 sometimes been treated as different species. In America, Cushman 

 (1933) and Schmieder (1939) have considered them to belong to the 

 same species, and Schmieder has discussed the reasons for this view in 

 some detail. Reichert (1910, Ent. Jahrb., Leipzig, vol. 20, pp. 180- 

 182) published observations on the European species that also support 

 the view that there is a single polymorphic species involved. Definite 



