54 Trans. Acad. Sci. of St. Louis. 



that it differs from pallidiceps in its sparser punctuation of 

 the head, finer and denser punctures of the elytra, in its less 

 elongate prothorax and much less elongate elytra, which are 

 said to be scarcely longer than the prothorax ; it occurs in 

 Arizona. Pallidiceps is much more closely allied to lepidus 

 than to nactus, but is a larger species with relatively narrower 

 head and darker coloration, besides differing in the male sexual 

 characters. 



Sphaeronia. 



The chief characteristics of this subtribe are the extremely 

 slender neck, formed nearly as in Stilicus and Scopaeus and the 

 small obtuse fourth palpal joint. These features are entirely 

 foreign to the Cryptobia and also to the related Lathrobia and 

 are correlated with so many peculiarities of structure as to 

 indicate the propriety of separating these minute, frail and 

 extremely interesting forms as a distinct subtribal group, for 

 which I would propose the above name. The group is prob- 

 ably peculiar to the American tropics, and, in addition to the 

 two genera here defined, will probably include several others 

 when those almost inexhaustible regions are more thoroughly 

 explored. The two following genera are defined upon exam- 

 ples kindly given me several years ago by Dr. Sharp, by whom 

 they were originally described : — 



Body less slender, almost as in Ababactus but more convex, moderately shin- 

 ing, very minutely punctured; head elliptically rounded at base behind 

 the eyes, which are moderate or rather small and slightly prominent, 

 placed at the middle of the sides, the frontal part before them abruptly 

 narrowed to a moderate degree, the antennal prominences large and 

 pronounced; labrum short, truncate, edentate, with a semicircular 

 median emargination ; surface more coarsely and confluently sculptured 

 in anterior half, finely and sparsely punctate posteriorly, the two post- 

 ocular foveolae of the Cryptobia distinct, the surface between them 

 feebly swollen; mentum transverse, biobliquely tumid; maxillary palpi 

 normal in form, the third joint obconical, longer than the second, finely, 

 closely pubescent; gular sutures narrowly separated, parallel, feebly di- 

 verging anteriorly; antennae rather stout, the joints closely joined, the 

 first nearly as long as the next four combined, strongly sigmoid, stout 

 and finely, closely pubescent, the second much longer than the third; 

 prothorax long and narrow, much narrowed anteriorly to the neck; 

 prosternum elongate before the coxae, broadly, transversely impressed 



