Pig. 20.— Northern Brenthiiin; a, lai-va ; b, pu- 
pa; c, beetle, female ; d, head of male; e, 4th 
antfcimal joint; /, leg; gl, parts of larval 
head. — Alter Riley. 
70 FIFTH REPORT OF THE ENTOMOLOGICAX COMMISSION. 
varies considerably, especially in .the males, both in length and breadth. 
It is of a mahogany brown, the thorax .smooth and highly polished, and 
the wing-covers strongly furrowed, 
shaded with deeper brown, and 
marked with narrow tawny-yellow 
spots. It is from one-fourth to a little 
over one-half an inch in length. The 
males are, contrary to the general 
rule in insects, almost invariably the 
larger. The males of the Brenthiaus 
are known to fight desperately for the 
female, and, as has been remarked by 
Mr. A. R. Wallace,* it is interesting, 
" as bearing on the question of sexual 
selection, that in this case, as in the 
stag beetles, when the males fight to- 
gether, they should be not only better armed, but also much larger 
than the females." (Riley.) 
According to Riley, in Missouri the eggs are deposited during the 
months of May and June. The female bores a cylindrical hole in the 
bark with her slender snout and pushes an egg to the bottom of the 
hole. 
" It requires about a day to make a puncture and deposit the egg. 
During the time the puncture is being made the male stands guard, 
occasionally assisting the female in extracting her beak ; this he does 
by stationing himself at a right angle with her body, and by pressing 
his heavy prosteruum against the tip of her abdomen ; her stout fore- 
legs serving as a fulcrum and her long body as a lever. When the 
beak is extracted, the female uses her antennae for freeing the pincers 
or jaws of bits of wood or dust, the antennae being furnished with stiff 
hairs and forming an excellent brush. Should a strange male ap- 
proach, a heavy contest at once ensues, and continues until one or the 
other is thrown from the tree. The successful party then takes his sta- 
tion as guard." (W. R. Howard, in Riley's Sixth Report.) 
Riley thinks that the larva lives but a single year, although larvae of 
different sizes occur in midwinter with the beetles. 
The larva. — Length, 0.55-0.75 inch ; di;«meter in middle of body, 0.05 inch. Body 
almost straight, cylindrical, 12-jointed, with a few faint hairs only on prothorax and 
around anus; thoracic joints short, bent a little forward, swollen and broadly and 
deeply wrinkled, with two especially prominent swellings on top of joints 2 and 3, 
converging towards head, and having each a granulated rufous spot ; the other joints 
with about three dorsal transverse wrinkles ; joints 5-9 subequal, as long as 1-3 to- 
gether, twice as long as 4 ; 10-12 diminishing in length, slightly swollen, the anus 
"The Malay Archipelago, p. 482. The line by the side of the insect in this and 
other cuts indicates the length of the insect, most of the sketches being enlarged 
views. 
