ICHNEUMON-FLIES — GELINAE: MESOSTENINI 401 



Polistes of the "Canadensis group" (P. annularis and P. exclamans 

 in North Carolina), while Pachysomoides julvus usually parasitizes 

 Polistes of the "Fuscatus group" (P. juscatus, P. rubiginosus, P. 

 metricus, etc.). 



This species ranges from southeastern United States to southern 

 Brazil. In the Neotropics it is divisible into several subspecies or 

 races, none of which have been distinguished in literature and named. 

 The typical subspecies (stupidus) was described from Mexico and this 

 is the one ranging northward into the United States, and for which 

 distributional and host data are given above. 



2. Pachysomoides fulvus (Cresson), new combinaiion 



Figure 334, c 



Mesostenus? fulvus Cresson, 1864, Proc. Ent. Soc. Philadelphia, vol. 3, p. 316; cT. 



Type: cf, Illinois (Philadelphia). 

 Mesostenus arvalis Cresson, 1872, Trans. Amer. Ent. Soc, vol. 4, p. 163; ?. 



Lectotype: 9, Bosque Co., Tex. (Philadelphia). 

 Biology: Dow, 1932, Psyche, vol. 39, p. 16. — Gaul, 1940, Canadian Ent., vol. 72, 



pp. 240-242. — Rau, 1941, Ann. Ent. Soc. America, vol. 34, pp. 364-365. 



Front wing 4.5 to 7.0 mm. long; punctures on mesoscutum moder- 

 ately strong, separated by about 0.4 their diameter; punctures on 

 mesopleurum small and crowded but strong enough to be easily visible; 

 basal and apical carniae of propodeum closer together than in P. 

 stwpidus. 



Head, body, and hind coxa fulvous, with whitish and fuscous 

 markings as in figure 334, c; palpi stramineous; scape and pedicel 

 blackish, whitish beneath in male, more or less fulvous beneath in 

 female; flagellum black, with a narrow white band; legs fulvous, the 

 front and middle coxae more or less whitish, especially in male; hind 

 tarsus brownish fulvous, usually the second through fourth segments 

 and sometimes apex of fu'st segment, or at least the third segment, 

 whitish. 



Specimens from the Rocky Mountains and westward have the 

 ground color usually a little darker and the whitish markings usually 

 a little less extensive than in specimens from the eastern half of the 

 continent. The most constant difference is in the whitish stripes just 

 above and below the sternaulus, present in specimens from the East, 

 usually absent or reduced in specimens from the West. 



Specimens (76 d^, 1859): From Alberta (Medicine Hat); Alabama 

 (Cheaha State Park); Arkansas; British Columbia (Robson, Tulip 

 Creek at Arrow Lake, and Waldies Road in Robson up to 3,500 ft.); 

 California (Antioch, Arroyo Seco Camp in Monterey Co., Conness 

 Glacier in Yosemite at 12,000 ft., Cypress Ridge in Marin Co., Davis 

 Creek, Elk Grove, Fresno, Huntington Beach, Los Mohnos, Mount 



