NORTH AMERICAN COLEOPTERA. 127 



From the sculpture of the elytra this species at first glance has 

 some resemblance to Diah. atrij)ennis. It may be readily known 

 from either of the species of the 11-jointed male sei'ies by the elytral 

 sculptuie and black scutellura. 



Occurs in New Mexico, Texas and Arizona ; in the latter region 

 near Yuma and Santa Rita Mountains (Wickham). 



P. geiitilis Lee, Proc. Acad. 1865, p. 208 ; var. nigripennis Lee, Trans. Am. 

 Ent. Soc 1868, p. 58; atripennis (partim ?) Say, Journ. Acad, iii, p. 461 ; ed. Lee, 

 ii, p. 224 ; var. texnnus Lee, Trans. Am. Ent. Soc. xii, p. 28. — Variable in color. 

 Antennse piceous, the three basal joints variegated. Head entirely yellovi^, 

 smooth. Thorax a little w^ider than long, sides nearly straight, disc convex, 

 often with a vague transverse depression, surface smooth, color entirely yellow, 

 or with a broad piceous stripe each side, with intermediate forms; scutellum 

 yellow. Elytra shining, microscopically alutaceous, impunctate, color variable, 

 either entirely black, side margin narrowly pale, or with side and suture more 

 widely yellow; epipleurse always pale. Body beneath piceous, sometimes en- 

 tirely yellow. Legs pale, often with the hind tibise darker. Length .10— .15 

 inch. ; 2.5 — 4 mm. 



Male — Antennje slender, second joint small, half as long as the third, joints 

 three to ten nearly equal ; middle tibife with a slight emargiuation on the inner 

 side near the tip; first joint of anterior tarsi not shorter than the second. 



Female. — Antennae slender, joints two and three equal, together a little longer 

 than the fourth, joints four to eleven equal ; middle tibiae not emarginate. 



Variations : 



Var. gentilis Lee. — Thorax with a broad black stripe each side occupying one- 

 third of the disc, but with the extreme margin pale. Elytra black, with the 

 suture, side margin and apex yellow; the underside of the body is usually en- 

 tirely yellow, but the abdomen may be piceous. 



Var. nigripennis Lee — Thorax similar to gentilis, but the lateral stripes show 

 more of a tendency to disappear, and one specimen before me has merely a black 

 spot each side in front. Elytra black. Body beneath black, the abdomen some- 

 times yellow. 



Var. texanus Lee— Tnorax entirely yellow, without trace of black stripes or 

 spots. Elytra black, with a narrow side margin yellow. Bodj' beneath entirely 

 yellow. 



It is probable that Say confounded the variety vigrijieintlt^ with 

 his atriventris, as the description of the latter coincides more nearly 

 with what we know as dorsalls, while his after remark that the an- 

 tenna^ are 10-jointed, shows that he must have had a specimen of 

 one (if the varieties of the present species before him. It is not 

 possible to make Say's name available, as he doubtless intended it 

 to apply to dorsalis Oliv. 



It seems rather remarkable that with what has been written of 

 Phylledhrus, the fact has not been discovered that this species is the 

 only one in which the male antennre are 10-jointed. 



TKANS. AM. ENT. SOC. XX. JUNE, 1893. 



