June 1899.] Casey: On American Coccinellid/e. 139 



Abdominal lines arcuate throughout, curving forward externally 2 



Abdominal lines extending outward externally parallel to the edge of the segment 

 and at a slight distance therefrom ; presternum relatively slightly wider between 

 the coxae, flat and wholly devoid ofcarinje ; genital or "sixth" ventral segment 

 unusually developed. ( Scymnobius sg. n. ) .71 



Abdominal lines gradually curving into the first suture externally and forming a part 

 thereof ; presternum scarcely as wide between the coxae as in Scymnobius, but 

 always rather flat and finely but strongly bicarinate, the carina straight, widely 

 separated and gradually converging ; eyes occasionally with a very small and 

 feeble emargination. ( Diomus Muls. ) 79 



2 — Abdominal plates entire, the bounding arc extending to the basal margin of the 

 first segment ; presternum rather narrow and convex between the coxae, with two 

 strong and well-developed carina;, which are but rarely abbreviated in front. 

 (Pul/us Muls.) 3 



Abdominal plates incomplete externally, the bounding arc not attaining the basal 

 margin ; presternum somewhat variable between the coxae, the carinae always 

 present but frequently abbreviated in front and more feebly developed than in 

 Pullus. ( Scymnus in sp. ) 64 



3 — The carinae entire or subentire 4 



The carinae greatly abbreviated, attaining about the middle of the presternum ; ab- 

 dominal plates very small, broader in nanus ; prothorax varying in form 63 



4 — Abdominal plates large and long, attaining the apical margin of the first segment ; 

 prosternal carina; arcuate, most narrowly separated well behind the apex ; body 

 oblong-oval, about one-half longer than wide, evenly pale flavo-testaceous above, 

 the head and under surface piceous-black ; last ventral segment and legs pale ; 

 head and pronotum very finely and remotely punctulate, the latter less remotely 

 and rather more visibly toward the sides, strongly transverse, with the sides 

 strongly convergent, broadly and evenly arcuate, almost continuous with the out- 

 line of the elytra, the latter finely, evenly and sparsely punctate, the hairs laid 

 longitudinally and evenly almost throughout ; under surface strongly and closely 

 punctured, the abdomen .more finely and less closely, the plates polished and al- 

 most impunctate throughout. Length 2.3 mm. ; width 1.5 mm. Colorado. 



flavescens, sp. nov. 



Abdominal plates normal, always shorter than the segment ; prosternal carinas gen- 

 erally straight but sometimes bent outward through a short distance from the 

 apex 5 



5 — Elytra uniform in coloration on the disk, not considering the apex 6 



Elytra bicolored on the disk, the pale areas either clearly defined and constant spots 

 or nubilate and variable ^ 57 



6 — Elytra entirely pale in color ; prosternal carina; entire, feebly converging through- 

 out 7 



Elytra black, with the common apex more or less broadly pale, the anterior margin of 

 the pale area biarcuate and generally very well defined 8 



Elytra black, with the apex not paler or more or less finely so, in which case the 

 anterior limiting line of the pale area is usually quite well defined but transverse 

 or not biarcuate 16 



