134 BULLETIN 66, UNITED STATES NATIONAL MUSEUM. 



The genus is restricted to parasites of Vespa and is at present 

 confined to Asia. 



Male. — At present unsatisfactorily described. 



Female. — Typically xenine, but larger than any other known 

 genus. Most nearly approaching the shape of Acroschismus. 



Triungulinid in general similar to that of Acroschismus. 



i. VESPiEXENOS CRABRONIS, new species. 



Host. — Vespa crabro Linnaeus; Japan. 



Female. — Length of cephalothorax 3.15 mm., greatest breadth 

 2.95 mm., breadth at spiracles 2.73 mm., breadth at base of head 

 2.35 mm., distance between mandibles 0.63 mm. Cephalothorax 

 rounded, constricted at base, widest point just behind spiracles, 

 spiracles dorso-lateral, not visible from ventral side, large convex; 

 margin deeply constricted in front of spiracles, then abruptly enlarg- 

 ing, from thence broadly convex to apex; mandibles very large, 

 quadrate, deeply emarginate at apex, apical angles large, obtuse. 



Type.— Cat. No. 12667, U.S.N.M. 



2. VESPiEXENOS MOUTONI Buysson (1903). 



Xenos moutoni Buysson, 1903, 1904. 



Host (typical). — Vespa mandarina Smith; also recorded on Vespa 

 magnifica Smith, Vespa nigrans Buysson; China (Yun-nam, Tse-kou, 

 Ngan-hoei, Yng-chan) . 



Female. — Length 17 mm.; length of abdomen 6 mm. Cephalo- 

 thorax yellowish, bordered with brown, extremity with a little sub- 

 triangular plaque, emarginate at apex; base of cephalothorax having 

 on each side a little whitish spiracle surrounded with brown; abdo- 

 men 9 segmented, the first narrowed into the form of a collar, the 

 last very large; a large yellowish band more chitinous, running the 

 entire length of the dorsum, represents the ventral brood canal. 



3. VESP^XENOS BUYSSONI, new species. 



Xenos moutoni R. du Buysson, 1906. 



The following description is taken from the account furnished by 

 Buysson in 1906. 



Host. — Vespa ducalis Smith; Hue, Annam; collected by E. Fleu- 

 tiaux, 1905, in Museum of Paris. 



Male. — Similar to Xenos vesparum Rossi, from which it is dis- 

 tinguished by its larger size, its smooth, brilliant body, without 

 velvety pubescence; by the much longer praescutum, which is about 

 twice as long as the width of its base, and finally by the more elongate 

 scutellum, with its less arcuate sides. Length 5 mm. ("Ecusson" 



