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 
aud 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 
