G. C. DAVIS. 237 



Exystoii exoelsu!* Cress. (Cfeniscns), Proc. Ent. Soc. Phil., iv, 262. 



2- — 8 mm. Black, with face, mouth-parts, cheeks, anterior orhital lines, scape 

 beneath, tejiiihe, line above and below, suture in front of it, the upper one re- 

 curving and reaching nearly to scutellum, anterior half of meso.steruum, pro- 

 sternum, patch hack of it, scutellums, broad baud across metathorax at base, 

 apical half of abdominal segments and all of legs, except sometimes the inner 

 portion of the femora and tibiae near base and at apex, which are black, lemon- 

 yellow; antennse reddish brown, paler at apex and beneath; wings hyaline, 

 veins brown, stigma semi-transparent, costal margin yellow : scutellum elevated 

 and with a transverse central ridge; petiole broad, spiracles distinct. 



%. — Differs in having the black encroach on the yellow on the head and ab- 

 domen somewhat, and in the thorax having besides the tegulae and scutellums 

 yellow, a line beneath tegulse and an oblong spot on anterior mesopleura. 



Five females and one male from Colorado, Montana and So. Cali- 

 fornia (type, coll. Araer. Ent. Soc). 



I^^xystoii flaveii!!« n. sp. 



9- — 6 mm. Black, with yellow markings extending still farther around the 

 eyes than in excehns, with markings on thorax the same except those on meso- 

 notura nearly wanting, and the band on metanotum narrow and irregular in 

 outline, with abdominal segments at apex entirely yellow, but on the first three, 

 not half yellow; four anterior legs, posterior trochanters and upper and lower 

 portions of posterior coxgg, yellow; remainder of hind legs, except coxEe black 

 at base, are a clear rufous; wings clear, hyaline; nervures and stigma color of 

 posterior femora; scutellum somewhat elevated ; third median cell of metathorax 

 strongly transversely reticulated. 



One specimen from Texas (type, coll. Amer. Ent Soc). 



Exyston nigrosciitiiin n. sp. 



% . — 8 mm. Black, with clypeus. mandibles except teeth, palpi, trapezoidal 

 orbital spots above clypeus and separated from it by a dark sutural line, tegulse 

 and trochanters yellow ; four anterior legs, except coxte and base of femora which 

 are black, and apical Jiiargins of abdominal segments two and the following yel- 

 lowish ferruginous; third segment, except broad, lateral, black stripes, and an- 

 nulus at base and middle of posterior tibise rufous; antennae reddish brown: 

 wings fuscous ; nervures and stigma brown; third discoidal cell twice as broad 

 in the middle as at base: the vein above broken and with stump, humeral cross- 

 vein of hind wing broken above middle; third median area of metathorax trans- 

 versely rugose, while those above it are longitudinally rugose : petiole scarcely 

 broadened behind; spii-acles not prominent: body rather coarsely punctured, 

 pilose. 



One specimen from Colorado (type, coll. Amer. Ent. Soc). 



Exystoii speciosii!<i n. sp. 



1. . — 6-7 mm. Black, with lower three-fourths of face, mouth-parts, except 

 teeth and base of mandibles, tegulse. tips of scutellums, four anterior coxae., all 

 trochanters and narrow margin on apical segments yellow : anterior legs and apex 

 of segments 2 and 3 and base of segment 3 of abdomen rufous; posterior tibiae 

 and tarsi piceous, the former slightly paler in the middle; antennae black, red- 

 dish toward apex beneath; wings fusco-liyaline, nervures and stigma reddish 



TRANS. .\M. ENT. .SOC. XXIV. . SEPTEMBKR. 1897. 



