90 | RHYNCHOPHORA. 
sexual characters given by Chapuis after testing them in various species of Tesserocerus, 
Platypus, and Crossotarsus. 
In female examples no chitinized structures, except the abdominal genital plates, 
can be found to form part of the genitalia. In the males the edeagus may be 
readily dissected out, and sometimes is to be found protruded; it is very simple, 
consisting of a gently curved tube slightly dilated at its free end, on the upperside of 
which is an oblique oval aperture. Within the body-cavity there lies on its ventral 
side a chitinous structure consisting of two slender rods attached at their anterior end 
to form a fork (Tab. 1V. fig. 17, edeagus of P. rugulosus). In Tesserocerus insignis, 
Saund., this additional piece consists of an unpaired rod running nearly the whole 
length of the edeagus, widened and furcate at each end. This is probably homologous 
with the Gabel of Lindemann’s descriptions of the male genitalia in Scolytide, and 
among the forms which he figures the whole apparatus is most like that of the European 
Scolytus multistriatus. A comparison of the edeagus and fork in various species does 
not lead one to hope that their examination will assist in specific determination. 
This group is highly specialized and, with the sole exception of the mouth-parts, 
remarkably uniform in essential points of structure, more so than any other group of 
Scolytide. The species vary a good deal in minor adaptive characters, such as the 
form of the scape, the armature of the tibie and of the male elytra; and, with the 
exception of one or two small groups which are still plastic and imperfectly segregated, 
they are remarkably distinct and easy to delimit, at least when the males are known. 
PLATYPUS. 
Platypus, Herbst, Natursyst. Ins. v. p. 128, gen. 84 (1793) ; Chapuis, Mon. Plat. p. 97. 
Cylindra, Duftschmid, Faun. Austr. iii. p. 87. 
The species of Platypus are found in every part of the world where there is suffi- 
cient woody vegetation for their support. The continent poorest in species is Europe, 
containing only two, of which one is confined to the Pyrenees. So far as our present 
knowledge extends, the headquarters of the genus are in Tropical America, the 
contingent next in importance having been furnished from the Oriental region, mainly 
through the labours of Wallace. 
The Central-American forms known to Chapuis amount to 22, from which number 
are excluded certain doubtfully distinct species which are not here treated separately. 
All these, save one, were described from Mexico, and chiefly from the material collected 
by M. Sallé, and now in our possession. 
The species here added, most of which have been obtained by Mr. Champion, amount 
to 23. Of these additional species, five, Platypus reichei, P. porrectus, P. alternans, 
P. armatus, and P. discicollis, have been described by Chapuis, all from Colombia, except 
P. alternans, which was recorded from Venezuela; the remainder are new. ‘The most 
important division in our fauna is that of the Platypi plicati, which includes the largest 
