REVISION OF STREPSIPTERA PIERCE. 125 



of A. Imbbardi. The writer was, however, unable to detect the 

 mesostigmatal lobes described for that species, but thinks they are 

 present. Genitalia similar with the exception that the oedeagus is 

 more abruptly curved, is obliquely depressed to the second turn, and 

 thence is much narrowed and very acute to the apex. 



Female. — Length of cephalothorax' 1.41-1.48 mm., breadth at 

 spiracles 1.40-1.61 mm., breadth at base of head 1.12-1.29 mm., 

 distance between mandibles at base 0.28-0.32 mm. Cephalothorax 

 light brown with very little color variation; as broad or broader than 

 long, laterally convex to spiracles, thence straight to point opposite 

 base of mandibles, apically very convex; spiracles not laterally promi- 

 nent; mandibles distant from lateral margins of head, quadrate; 

 inner angle armed with a large outward curving tooth. 



Type.— Cat. No. 9826, U.S.N.M.; Hubbard and Schwarz collection. 



3. ACROSCHISMUS NIGRESCENS Brues (1903). 



Xenos nigrescens Brues, 1903, 1905. 

 Acroschismus nigrescens Pierce, 1908. 



Host. — Polistes rubiginosus Lepeletier; Austin, Texas (males, fe- 

 male). P. rubiginosus and P. annularis (?) (males, females); Paris, 

 Texas (Brues, 1905). 



The original description by Brues is as follows: 



Male. — Length 4.5 mm. Black above, abdomen often gray at base, head above 

 piceous, antennas dark cinereous. Mandibles black at base, lighter at tips. Palpi 

 cinereous, indistinctly two-jointed, the second joint one-half as long as, and connate 

 with, the first ventrally, where no suture is visible; above it appears indistinctly 

 constricted off from the first. Prothorax black or piceous above, somewhat lighter 

 on the sides; elytra cinereous. Dorsum of thorax fuscopiceous, lighter on the sides 

 and at tip of post-scutellum. Abdomen usually black, sometimes gray at base and 

 with two indistinct longitudinal dark bands. Wings delicate, pale hyaline, much 

 as in (X.) pallidus except that the subcostal nervure (=third, or radial) is interrupted 

 near the middle (node) as in A', peckii (=Acroschismus wheeleri Pierce); all the pos- 

 terior veins nearly obsolete. Body below in great part piceous, abdomen black or 

 gray below. Legs cinereous, darker above on femora, tibiae, and tarsi. 



Female. — Length 9-10 mm. Exposed surface of head (=cephalothorax) black on 

 posterior two-thirds, orange on anterior one-third, the line dividing the two colors 

 straight transverse. Anterior half of thorax (=basal segments of abdomen) yellow, 

 its lateral wrinkles ferruginous. Dorsal (sic, =ventral morphologically, although 

 uppermost) stripe of abdomen (=area of brood canal) brownish, nearly half as wide 

 as the body, at base narrowed and faded out posteriorly. Genital pores on median 

 line near posterior margin, distinct. 



Described from one female and four male specimens, collected and bred at Austin, 

 Texas, during October, 1901 (Brues, 1903). 



Triungulinid : Length 0.28 mm. Oval, head obtusely rounded, anteriorly. Head 

 and thorax together slightly longer than the abdomen. Head a little less than half 

 as long as the thorax, almost semicircular when seen from above, being truncate be- 

 hind. Eyes large, strongly pigmented. Oral opening large, almost contiguous with 

 the eyes below; mouth parts consisting apparently of a short proboscis-like organ 

 with chitinous sides. No antenna? or other tactile organs to be seen. Thorax one 

 and one-half times as long as wide, consisting of three nearly equal transverse seg- 



