OTIDOCEPHALUS. 231 
being in great part replaced by Erodiscus and its allies on the southern continent. 
A considerable number of species have been already described from Mexico, the types 
of all but one of which have been seen by me, but none from the rest of our region. 
About seventy are here recognized as distinct, many of which appear to be confined to 
particular districts, and it is therefore very difficult to decide as to the true limits of 
some of the very closely allied species. In addition to the large amount of material 
contained in our collection, I have also examined numerous Central-American 
Otidocephali belonging to the Museums of Stockholm, Berlin (including the Mexican 
series got together by the late Julius Flohr), Dresden, and London, and various Mexican 
species communicated by Herr R. Becker of Berlin. 
The North-American O. levicollis and the Mexican O. dugesi have been bred from 
the galls of a Cynips on oak, and 0. dichrous has been found in Florida on old leaves 
of Chamerops. The numerous forms taken by myself were mostly beaten from the 
branches of oak and other deciduous trees. Fifteen or sixteen species have been 
described from North America and Mexico respectively, three from Lower California, 
and a few from the Antilles and South America. 
The following table is based mainly upon the form of vestiture and the shape of the 
femoral tooth, which is present in all of them*. ‘The tarsal claws are always more or 
less appendiculate :— 
a. Femora unidentate. 
a’. Head without supra-ocular ridge. 
a’. Prothorax not narrowed behind, the sides forming an almost con- 
tinuous outline with those of the elytra; general coloration brassy . Species 1. 
6”. Prothorax narrowed behind, and at the base much narrower than the 
elytra. 
a’, Lateral sulci of the rostrum very deep, broad, and almost smooth ; 
prothorax long and cylindrical; elytra with scattered, coarse, 
curved, squamiform hairs only. . . . » . + + + + « « ~ Species 2. 
b/, Lateral sulci of the rostrum shallower, rugose or punctate. 
a’, Elytra with the vestiture simple, decumbent or semierect, without 
intermixed darker setze. 
a’, Prothorax with a depressed or flattened, rugulose, thickly 
pubescent space on the disc posteriorly; elytra seriate- 
punctate, the interstices almost smooth ; femoral tooth 
moderately large, triangular . . . . . . - . « . ~ ~ Species 3, 4. 
b°. Prothorax without a depressed rugulose space on the disc. 
a°’. Elytra closely, confusedly punctate, at most seriate-punctate 
near the suture, uniformly clothed with fine grey pubescence. Species 5. 
b°. Elytra seriate-punctate, the interstices closely punctured. 
a’. Pubescence coarse and close, white and fulvous intermixed. Species 6. 
6". Pubescence finer and sparser. . . . . . . . . . . Species 7. 
* This is absent in the N.-American O. cavirostris, Casey, and the Cuban 0. poey?, Chevr. 
