126 BULLETIN 66, UNITED STATES NATIONAL MUSEUM. 



ments. Each segment below bears a pair of very small and delicate legs. The coxge 

 are all greatly swollen and globose, those of each side contiguous with one another 

 and the pairs only moderately separated along the median line. Each coxa is hol- 

 lowed out below and the trochanter sunk within it. Femora slender, enlarged some- 

 what at base, bearing a spine apically. Tibiae slender, of equal width, the hind ones 

 with a preapical spine. Tarsi greatly reduced, those of the four anterior legs scarcely 

 distinguishable from the tips of the tibiae furnished with a pulvilliform appendage, 

 the posterior pair elongated, with a styliform appendage. Abdomen consisting of 

 nine short, transverse segments and an elongated tenth segment which encloses the 

 extrusible tip of the abdomen (eleventh segment?). The dorsal sclerites reach far 

 down on the sides, as do also those of the thorax, making the underside of the body 

 somewhat concave. Tip bearing two approximated bristles, each as long as the abdo- 

 men, in addition to a much shorter one at each lateral angle of the last segment 

 (Brues, 1905). 



Brues's figure of the triungulinid is evidently in error, as it is given 

 fourteen abdominal segments. 



Female. — The following description is drawn from the type speci- 

 mens: 



Length of cephalothorax 1.49 mm., breadth at spiracles 1.27 mm., 

 breadth at base of head 0.97 mm., distance between mandibles at 

 base 0.28 mm. Cephalothorax light brownish, darker on basal two- 

 thirds except on center of disc; deeply emarginate at base, oblique, 

 convex to point opposite base of mandibles, apex very convex; 

 spiracles not laterally prominent; mandibles distant from lateral 

 margins of head, oblique, oblong, with outward curved tooth on 

 inner angle and outer angle prominent rounded. 



4. ACROSCHISMUS PALLIDUS Brues (1903). 



Xenos pallidus Brues, 1903, 1905. 

 Acrosckismus pallidus Pierce, 1908. 



Host. — Polistes annularis Linnaeus; Austin, Texas (Brues, 1903); 

 Paris, Texas (Brues, 1905). 



Brues originally described this species as follows: 



Male. — Length 2.25 mm. Head and thorax above fuscous, below, very pale luteous, 

 antennas with the first two joints luteous, the rami of the fourth joint (third and fourth 

 joints) yellowish gray, their spots pale. Eyes black, their hemispherical facets of the 

 usual size. Mandibles pale luteous, white at tip. Palpi white, distinctly two-jointed, 

 the first joint nearly twice as long as the second and obliquely truncate at apex; 

 second joint oval. Prothorax and mesothorax fuscous; elytra pale, grayish at tip. 

 Dorsal sclerites of the metathorax shaped a« in X. peckii (=Acroschismus wheeleri 

 Pierce) ; fuscous, darker on the post-scutellum. Legs pale luteous, tarsi slightly gray- 

 ish above near tips. Wings pale hyaline, the nervures very delicate and not pig- 

 mented along their edges. The costal margin darkened for nearly its entire length. 

 Abdomen finely transversely wrinkled on the dorsal surface; grayish yellow, blackened 

 above, especially posteriorly. Ventral plates honey yellow, hypopygium (ninth 

 segment) yellow except the dorsal piece (tenth segment), which is grayish. 



Described from 24 male specimens, all bred from individuals of 

 Polistes annularis Linnaeus, at Austin, Texas, during May (Brues, 

 1903). 



