WILLIAMS: LARRID^ OF KANSAS. 175 



o . Pygidium well defined, naked and broadly triangular. 

 7 . Pygidium smaller and less distinct in this sex; eighth ventral 

 segment rounded out or at most slightly emarginate. 



A genus represented by small species, of which there are about a 

 dozen in the United States. 



Key to the Species of Plenoculus. 



Abdomen black davisi 



Abdomen red, black apically apicalia 



Plenoculus davisi Fox. 



Plenoculus davisi Fox; Psyche, Nov. 1893, p. 5-54. 



Plenoculus davisi Fox; Proc. Acad. Nat. Sci. Phil., .537; 1893. ^ 5 . 



o . Clypeus emarginate mesad; three to five lateral teeth; thorax 

 minutely punctate; propodeum finely granulate, a median impressed line 

 and some short transverse striae at base, sides delicately striate. Black; 

 mandibles, e.xcept tip, tegulae, tibias and tarsi, more or less yellowish, 

 abdominal segments apically testaceous, the last segment reddish at tip. 

 Length, .5-6 mm. 



7 . Anterior margin of clypeus strongly rounded out or slightly pro- 

 duced mesad; ventral abdominal segments 3-6 with a transverse row of 

 tubercles. Black; clypeus and scape beneath, tubercles, tegulse and disc 

 of prothorax, apex femora, tibiae except the inner side of the two an- 

 terior pairs, and tarsi, bright yellow. Length, 4.5-5 mm. 



Structurally much like pvojnngnus and apicalis. 



A single :f taken in Graham county, August 16, 1912, seems to be- 

 long here. The clypeus has its lateral angles sharp, the median portion 

 produced much as in apicalis, and the light yellow markings, disposed 

 rightly for the species, are here light yellowish-brown to brownish in- 

 stead of yellow. Length, 4.25 mm. 



Plenoculus apicalis n. sp. 



(Fig. 20, wings; 43-45, antennae; 76 and 77, clypeus; 102, pygidium, 

 g ; 103, tip of J- abdomen.) 

 o . Anterior margin of the clypeus with four, or an additional fifth 

 tooth on each side of the median emargination ; front finely granulate; 

 median impressed line from behind fore ocellus not extending to base of 

 antennae, where it is partly replaced by a raised line; a .short curved 

 furrow between each posterior ocellus and eye; first joint of flagellum a 

 very little shorter than either second or third; scutum and scutellum with 

 fine, close punctures, the sides finely and indistinctly gi-anulate-striate; 

 disc of propodeum finely grahulate, the strong median furrow traversed 

 by a few separate and indistinct striae; the disc largely naked, its base 

 with some short radiating stria», the sides about like the thorax, posterior 

 face with a wedge-shaped depression and polished median impression 

 within; legs stout, rather spinose, tarsal comb moderate, the spines 

 thereon about as long as the diameter of the first tarsal joint; venation 

 normal; abdomen inpunctate, except toward the apex (at the origin of 

 the hairs) ; pygidial area shining, sparsely large-punctate, the bounding 

 carinae low. Black; mandibles, except tip and lower edge, yellowish to 



