74 



PRELIMINARY LIST 



ville, August 23d; Trinidad, May 14th; Montrose, Juae 24th 

 (Crillette). Fort Collin^, October 7th; Dixoa's Canon, May 

 6th; Steamboat Springs, July 15th, on willow (Baker). 



A common species everywhere. There seems to be con- 

 siderable variation in the form of the last ventral segment 

 in the female. 



Idiocenis amoenus VanD. 



Det. VanDuzee. 



Colorado (VanDuzee, 4). 



Horsetooth Mountain, July 4th; Steamboat Springs, July 

 26th; Montrose, June 24th (Gillette). On Red Stone Creek 

 twelve miles south-west of Fort Collins, August 1st (Baker). 



Idiocenis interruptiis n. sp. 



Female; Face aljout a ninth wider than long; clypeus one-half longer than broad, 

 gradually broader towards the almost truncate apex, basal suture straight: lorae a li'tle 

 longer and almost as broad as the clypeus: genae rather narrow, rlie outer margins 

 straight, attaining tip of clypeus, modern tely broad 

 below the lor; e; front oi e fourth longer than 

 broad and nearly three times as long as tlie clypeus. 

 Face, prunotum and scutellum finely shagreened. 

 Vertex finely, transversely wrinkled, about one- 

 fourth longer at tlie eyes than at the middle, dis- 

 tance between the eyes a little less than five and a 

 lialf times the length at the middle. Pronotum a 

 little more than twice as broad as long, and three 

 and a half times tlie length of the vertex; the 

 curvature a little more than two-tliirds the length 

 of the pronotum: transverse groove of scutellum 

 angularly bent forward and obsolete at the center, 

 appearing as two oblique lunate depressions. Last 

 ventral segment with tlie hind margin shallowly 

 notched and the posterior angles obliquely cut off. 

 Color pale yellow marked with brown and black; 

 face mottled abiive with brown; eyes brown. Vertex 

 brown with a yellowish white line next the eyes, 

 and a median longitudinal white line, and a small 

 black spot on either side. Pronotum brown with a 

 broad median longitudinal white band, anterior 

 margin whitish with about four small blai-kisli spots 

 on either side; scutellum whitish with a large black 

 spot just within the basal angles on either side; a 

 median brown line between base and transverse 

 groove, forked beyond and extending nearly to tlie 

 tip: a small black spot on eitlier sidc.iu-t l)i fore the 

 ends of the transverse groove. Elytra wliitish sub- 

 hyaline, with an obli(iue brown band on the middle 

 extending down and forward, veins brown inter- 

 rupted with white, a large wliite spot on the middle 

 of tlie clavus, with a smoky spot in front and another on the tip; all Iieneath uni- 

 colorous, legs slightly waslied with rufous, propleura with a black spot. Length 5 mm. 



Male; Ditfers from femjile as follows; lielow deeper yellow, white lines next the 

 compound eyes obsolete, otlier light marking on the vertex and iironotum yellowish, most 

 of tlie dark marking* darker; front margin of anterior coxae wiih a hirge black spot, and 

 narrow black lines on tlie outer sides of all the tibiae; compound eyci jet black; black 



