A REVISION OF NORTH AMERICAN CHRYSOBOTHRINI 73 



Pronotum nearly twice as wide as long, narrower at base than at apex, widest 

 near apex; sides sinuate and strongly, arcuately converging from near apical 

 angles to posterior angles, more strongly on posterior third; anterior margin 

 sinuate, with a broad, obscurely rounded, median lobe; base slightly emarginate 

 on each side, the median lobe slightly produced, and truncate in front of scutel- 

 luni ; disk moderately convex, without a median depression or smooth callosities ; 

 surface sparsely, finely, shallowly punctate, finely, transversely rugose, especially 

 at sides, intervals densely granulose. 



Elytra slightly wider than pronotum, twice as long as wide ; sides parallel 

 from humeral angles to apical third, then arcuately converging to tips, which 

 are separately broadly rounded ; lateral margins coarsely serrate ; basal de- 

 pressions broad and moderately deep; humeral depressions broad and shallow; 

 surface glabrous, densely, finely punctate, more densely and somewhat rugose 

 toward base, intervals indistinctly granulose. Each elytron with four more 

 or less distinct longitudinal costae, the first elevated on apical half, the others 

 indicated by more or less distinct lines, which are interrupted by the foveae, 

 and with three densely punctured foveae ; first just in front of middle, inter- 

 rupting the second costa ; second at apical third, interrupting the third costa; 

 third slightly behind the second fovea, interrupting the second costa. 



Abdomen beneath rather densely, coarsely punctate, smooth along anterior 

 and posterior margins of sternites, densely clothed at sides with long, semi- 

 erect, white hairs, with vaguely indicated lateral callosities, intervals densely 

 granulose; basal sternite longitudinally depressed at middle; last visible 

 .sternite broadly, deeply, arcuately emarginate at apex, without a submarginal 

 ridge, lateral margins serrate ; eighth tergite angularly emarginate at apex, 

 coarsely punctate, densely granulose, but without a longitudinal carina. Pro- 

 sternum flat, coarsely, confluently punctate, transversely rugose, densely granu- 

 lose, densely clothed with long, recumbent, white hairs, with a distinct, broad, 

 median lobe in front. Anterior femur with a broad, rather acute, triangular 

 tooth, which is coarsely dentate on outer margin. Anterior tibia strongly 

 arcuate, with a short, indistinct dilation at apex; middle and posterior tibiae 

 straight. Genitalia similar to those of lateralis. 



Length 7.5 mm., width 2.7 mm. 



Eedescribed from the male type, No. 2686, in the Museum of Com- 

 parative Zoology, Cambridge, Mass. 



Female. — Differing from the male in having the antenna uniformly piceous, 

 the basal sternite of the abdomen convex at middle, the last visible sternite 

 broadly, shallowly emarginate at apex (nearly truncate), the eighth tergite 

 broadly rounded at apex, longitudinally carinate, and broadly depressed on each 

 side of the carina, and the anterior tibia unarmed at apex. 



Type locality. — Of debilis, Ohio; type, No. 2686, simply labeled 

 with a yellow disk. Of disjuncta, Arizona; type, No. 2687, simply 

 labeled with a silver disk. Both types in the Museum of 

 Comparative Zoology. 



DISTRIBUTION 



From material examined : 



Arizona: No definite locality, type of disjuncta, labeled, with a silver disk, 



which indicates the valley of the Gila. 

 California: San Diego County (D. W. Coquillett). Indio, April 4, 1925 (R. E. 



Campbell). Panamint Valley, April 1891; Death Valley, April 1891 (A. 



Koebele). 

 Nevada: Overton, May 12, 1930 (E. W. Davis). 



Chamberlin (1926) records it from various localities in Arizona, 

 California, Colorado, Lower California, New Mexico, Texas, and 

 Utah, but many of these records refer to lateralis and prosopidis. 



Hosts. — The adults have been collected on mesquite (Prosopis 

 juliflora (Swartz) De Candolle) in Death Valley, Calif., by A. 

 Koebele, and on honey mesquite {Prosopis juliflora glandulosa (Tor- 

 rey) Cook) at Overton, Nev., by E. W. Davis. Burke (1918) re- 



