300 GEO. H. HORN, M. D. 



O. plictitlllst Fall.— Oblong, dilated posteriorly, pieeous black, opaque. 

 Head yellowish, occiput black. Antennae rufous, club darker. Thorax yellow- 

 ish, disc and sides pieeous, transverse, anterior angles prominent in front, behind 

 them the sides are deeply sinuate, the three-fourths posterior to the sinuation 

 straight and deeply convergent, surface coarsely punctured and with a T-shaped 

 callosity in the middle of the disc. Scutellum yellow. Elytra oblong, dilated at 

 apex, each at tip obliquely truncate, more prolonged at the suture, base broader 

 than the thorax, humeri obtuse, entire margin denticulate, disc flattened, surface 

 with numerous acutely elevated, short, oblique plications more or less anastomos- 

 ing, the intervals punctured. Legs pieeous, the femora and tibiae at base and tip 

 paler. Length .18 inch; 4.5 millim. 



This species is widely distributed, but rare. Occurring in Illinois, 

 South Carolina and Texas. Its peculiar sculpture and clavate antennae 

 make it one of the most easily known species in our fauna. 



O. margiiiicollis n. sp. — Beneath pieeous, above yellowish, apical half of 

 the elytra brown. Antennae pale yellow, the third joint nearly as long as the 

 two following together. Head feebly punctured. Thorax nearly twice as wide as 

 long at middle, sides nearly straight behind, arcuate in front and slightly sinuate 

 behind the prominent front angles, lateral margin narrowly explanate and trans- 

 lucent, especially in front, disc slightly convex, vaguely depressed posteriorly, 

 surface coarsely cribrately punctured. Elytra elongate, quadrate, arcuately nar- 

 rowed at middle and rather abruptly dilated at apex, margin serrate, surface with 

 elevated ridges formed as follows : An irregular carina begins at the base within 

 the humeral angle and extends somewhat sinuously to the middle, where it ab- 

 ruptly forms an intricate network of strongly elevated ridges, extending over 

 nearly the entire apical half of the elytra, on each side a short distance from the 

 apex of the suture is a lam ini form tubercle, between the ridges the surface is 

 coarsely punctured, cribrate at the basal portion of the elytra. Legs yellowish, 

 femora and tibiae broadly annulate, with brown at middle. Length .20 inch: 5 

 millim. Plate IX, fig. !>. 



This species is larger and relatively broader than plicatula. It differs 

 primarily in color and very obviously in sculpture. In the preceding 

 species the elytra are covered with oblique plications, but in the present 

 species the elevations are confined to the apical half of the elytra and are 

 more irregularly sinuous instead of oblique plications. 



Occurs in Arizona. 



Stenopodiides. 

 Form oval, moderately robust. Elytra with alternate intervals feebly more 

 convex. Antennae very short, extending but very little behind the anterior mar- 

 gin of thorax, 8-jointed, last two joints forming an elongate oval club. Tarsi not 

 dilated, clothed beneath with silken hairs, third joint not bilobed, scarcely emar- 

 ginate. fourth joint as long as the others together, moderately stont, claws rather 

 long, feebly curved, divergent. 



This assemblage of characters defines a'very distinct group, and the 

 structure of the tarsi has nothing approaching it as far as known among 

 the Phytophaga, except in Haemonio . Can it be possible that the pres- 

 ent insect is subaquatic in its habits in the manner of that genus ? 



