STATES OF INSECTS. (Jmago.) 325 
Tabanus, and many other two-winged flies, the male eyes 
meet at some point below the stemmata, and above the 
antennz. In the former they touch more at an angle; 
for the vertex forming a narrow isosceles triangle, and 
for the anterior part of the face one nearly equilateral : 
while those of the female are separated by a considerable 
interval. In Heptatoma and Hematopota in that sex, 
a similar interval obtains ; while in the other, after form- 
ing 2 minute short triangle, they unite for a considerable 
space, and then diverging, form the face. This is also 
the case in Tabanus ; but in the female, the space that 
intervenes between the posterior part of the eyes is much 
narrower than in these two cognate genera of the horse- 
flies. In some others of this order, as Musca, the eyes 
of the male do not touch, but approach posteriorly 
much nearer to each other than those of the other sex. 
In a few instances the sexes vary even in the number of 
their eyes, as well as the size. This occurs in some spe- 
cies of Ephemera (E. diptera, &c.), in which the male, 
besides the common lateral ones, has two large and 
striking intermediate eyes, that sit upon vertical pillars 
or footstalks ?. 
2. The Trunk. The thorax of many coleopterous 
males, especially of the Dynastide and Copride amongst 
the petalocerous tribes, exhibits very striking differences 
from that of the female. In many ZLucani the lateral 
angle is more prominent. In Anthia it is bilobed poste- 
riorly, while in the last-mentioned sex it is entire’. In 
Phaneus carnifex it is elevated into a plane triangular 
space, with the vertex of the triangle pointing to the 
* Pirate XXVI. Fic. 39. De Geer ii. 651. 659. 
» Voet Coleopt. i. t. xxxix. f. 47, 48. ¢. 46. 2. 
