70 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



Fig. 20.— Northern Brenthian ; a, larva; b, pu- 

 pa ; c, beetle, female ; d, head of male ; e, 4th 

 antennal joint; /, leg; g-l, parts of larval 

 head. — After Kiley. 



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 Brenthians 

 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 prosternum 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. K. 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 ; ditiiiieter 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. 



