COLEOPTEEA. 
41 
1. Genus PTYCHODERES, Sch. 
As above stated, this genus is here regarded as restricted by Schonherr, 
and forms one of the most homogeneous genera in the family. The resem¬ 
blance of the species is so great that they not only have the same sculpture, 
but their coloration is also disposed in the same manner. To the charac¬ 
ters given by Schonherr I have to add the following:— 
Dorsal ridges of the rostrum always more elevated and distinct in the 
male than in the female: the median continued in front between the eyes, 
where, close to and on each side of it, there is another very short and 
thinner, and also less distinct in the female: this often joins the lateral 
one of the disc of the rostrum at its anterior extremity, at the place where 
it runs obliquely towards the eye. Rostrum a little dilated at the apex, 
longer in the most developed males, but always shorter in the females than 
in the less developed males. Antennae of the males gradually more elon¬ 
gated, according to the development in size of the specimens: generally, 
in the largest, they are nearly as long as the body, sometimes longer, and 
they gradually decrease in length with the proportional diminution of size 
of the specimens. Taking Pt. elongatus as the type of this curious varia¬ 
tion, of the numerous specimens I have seen, hardly one example smaller 
than another has occurred with a more elongate antenna. Males, two or 
three times smaller than the largest specimens, have the antennse reaching 
at least the base of the elytra; whilst those of the females (which compara¬ 
tively vary very slightly in size, and reach at least the intermediate size of 
the males) hardly reach the posterior carina of the thorax. The clava, 
though it seems in the males to become gradually narrower proportionally 
as the body increases in size and the antennae become more elongate, in¬ 
creases only in a decided manner in its first joint, which corresponds with 
the gradual elongation of the joints of the funiculus, the two terminal 
joints proportionally increasing very slightly. In the females the clava is 
broader than in the smallest males (proportionally), and consequently less 
elongate, having, especially, its terminal joint much shorter, more conic 
and subpyriform. The thorax affects a similar outline in all the species 
with a depression on the upper side; its posterior carina also varies very 
little: its coloration beneath is like that of the abdomen and pectus, more 
or less whitish tomentose, with a sublateral narrow blackish band, always 
G 
