STATES OF INSECTS. (Imago.) 311 
the rudiments only of which are to be traced in the fe- 
male*. Other species go beyond any known quadru- 
peds in the number of horns that arm their heads. Thus 
Ditomus calydonius one of the ground-beetles (Eutre- 
china) has three equal horns®. ‘The same number dis- 
tinguishes Onthophagus Bonasus ; but the intermediate 
one is very short. In Goliathus Polyphemus the middle 
horn, on the contrary, is much longer and thicker than 
the lateral ones, and forked at the apex; so that it looks 
as if it had four of these weapons*. A little Diaperis 
(D. viridipennis), a native of Carolina, has four horns 
upon the head of the male; namely, two long ones on 
the occiput, and two short dentiform ones on the nose. 
In a species nearly related to this, sent me by Professor 
Peck from New England, there is a cavity between the 
two occipital horns. ‘The same number distinguishes 
Onthophagus quadricornis. 'The situation also of the 
horns varies: In some it is in the mzddle of the head, 
as Oryctes nasicornis, Copris lunaris, &c.: in others, as 
in Onthophagus nuchicornis, Xiphias, &c. it is a process 
of the occiput or hind-head; and in O. Oryx the two 
horns proceed from the anterior part of the head. In 
the other sex, in insects the head of whose males is armed 
with horns, they are usually replaced by mere tubercles, 
or very short elevations, as you may see in the female of 
Copris lunaris ; or by transverse ridges, as in the Ontho- 
phagi: or else the head is without arms, and quite smooth, 
as in Diaperis, Phaleria, &c. What may be the use of 
* Oliv. no, 83. 160. ¢. vi. f. 60. d.¢.v. f. 45. 9 ? Schonherr has 
made these a subgenus (Gorgus) of his genus Cratosomus separated 
from Cryptorhynchus. Syn. Ins. iy. 279. 
® Oliv. no, 36. é. ii, f. 12. © Ibid. no. 6. t. vii. f. 61. 
