ART. 23 REVISION OF THE BEETLE GENUS OEDIONYCHIS BLAKE 39 



approaching one-third the width of the head. In circumdata the 

 shape of the elytra is more quadrate, in ohsidiana the prominences 

 at scutellar angle are more distinct. The punctation in circumdata 

 as a rule is coarser and the surface only moderately shining. The api- 

 cal pattern of ohsidiana never occurs in circumdata^ the latter having 

 only a slightly wider yellow margin at apex. In both ohsidia7ia and 

 circumdata are forms having two oblique marks or dots, reddish 

 brown or yellowish, on upper half of elytra. 



I have found the beetles feeding in early spring on the tender 

 leaves of beech {Fagus grandifolia) and walnut {Juglans cinerea) 

 as well as feeding on the leaves of Plamtago lanceolata and Verbena 

 Mfrticae folia. 



32. OEDIONYCHIS OBSIDIANA (Fabricius) 



Figs. 37, 38. 39, 40, 41 



Oalleruca otsidiatm Fabricius, Syst. Eleuth., vol. 1, 1801, p. 499. 

 Altica ohsidiana Olivier, Ent., vol. 6, 1808, p. 691. 



Oedionychis quercata Horn, Trans. Amer. Ent. Soc, vol. 16, 1889, p. 194 (ni>t 

 Fabricius). 



Small, oblong-oval, shining, piceous with pale margins and pale 

 apex to elytra. Antennae half length of body, slender, pale with 

 darker terminal joints, third and fourth joints nearly equal, fourth 

 occasionally slightly longer. Head more or less piceous, very faintly 

 and finely punctate; median groove distinct, interocular space con- 

 siderably less than half width of head. Pronotum over twice as 

 wide as long, with wide, pale, explanate margin, arcuately narrowed 

 anteriorly, shining, with few faint, indistinct punctures; entirely 

 piceous except for margin, occasionally a lighter median streak. 

 Scutellum piceous. Elytra oblong-oval with explanate margin; 

 basal callosities at scutellar angle and humeral prominences, especially 

 the former Avell marked, depression between deep; shining, punc- 

 tation fine and shallow, indistinct toward apex; entirely piceous 

 except for pale margin and apex; apical pattern differing from 

 broad, pale apical margin of circumdata by having a somewhat 

 scalloped outline. Body beneath finely pubescent, meso- and meta- 

 sterna and abdomen dark brown or piceous, sometimes femora of 

 hind legs piceous, anterior legs and tibiae and tarsi of hind legs 

 paler, epipleura usually pale. 



Length. — 3 to 4 mm.; width 1.8 to 2 mm. 



Type locality. — Carolina. 



Distribution. — Maryland, North Carolina, ''Carolina," Georgia, 

 Florida, Alabama, Louisiana, Tennessee, Arkansas. 



Specimens from Florida in the National Museum differ from the 

 typical form by having elytra almost entirely black with only the 



