INSECTS AFFECTING FOREST TREES. 



517 



biz'i//<itiis Kiiby. It varies in color from light brown to almost black, is cjMindrical 

 in shape and about % of aH incli long. The shape of the antennal club, and the 

 sculpturing of the dorsal surface are shown in figure 16. This species and the 

 following have divided eyes, the two divisions being some distance apart and con- 

 nected only by a narrow dark strip, which is best seen in recently transformed, 

 light colored individuals. The galleries of this insect may extend to some 

 depth in the wood, lateral burrows being given off at intervals and the brood cham- 

 bers occurring very close together, almost like the cells of a honey bee. The walls 

 of the galleries and brood chambers are deep black, as in the case of allied species. 



Xatitrnl Enci>iics. A predaceous beetle, Colydiuni lincola Say, has been recorded 

 by Dr. Hopkins as occurring in the burrows of this species. Another small beetle, 

 Ips saiigniiiolcntns Oliv., was also found by him in association with this species, feed- 

 ing on the sap wood of sugar maple. 



Monarthriiiii iiiali I'itch. 



This is a minute, reddish-brown cylindrical beetle, about 3/32 of an inch in length, 

 which may be found in cylindrical, black-walled galleries in dead beech, spruce and 

 other trees. It was taken by the writer August 21, 1900, at Floodwood, in a fallen 

 beech which had begun to decay, and was also found by him in a spruce stump at 

 Axton. It has been recorded by various writers as breeding in a number of hard 

 and soft wood trees. 



Life History. Mr. H. G. Hubbard has recorded some interesting observations on 

 the life history of members of this genus. He states that the males assist the 

 females in forming new colonies, and that the young are raised in 

 separate pits or cradles which they do not leave until maturity is 

 attained. The galleries constructed by the female beetles extend 

 deeply into the wood, with their branches mostly in a Iiorizontal 

 plane, figure 18. The mother beetle deposits her eggs in circular 

 pits which she e.xcAvates from the galleries in two opposite series 

 parallel with the grain of the wood. An egg is deposited in each and 

 the cavitv packed with chiijs taken from the fungus bed and uijon '^"^- '7- ^^'onar- 



' THRUM MALI. 



which ambrosia has begun to grow. The young grubs as soon as they .^ptrr hubbakd, 

 hatch eat the fungus and eject the refuse from their cradles. At \l „ ,1. \.!i'^^'' 



*J ■' I) IV, ENT. BUL. 7i 



first they lie curled up in the pit made by the mother, but as they "• s- 97- 

 grow larger, they deepen the cradle with their own jaws until when full grown they 

 slightly exceed the length of the fully extended grub. The young swallow the 

 wood which they excavate but do not digest it. It passes through the body 

 unchanged in texture and is e.xcreted in pellets and stained a yellowish color. A 



