INSECT ENEMIES OF EASTERN FORESTS 635 
because they act as important agents in pollinating flowers and be- 
cause of the value of their honey. They are not often considered in- 
jurious to forest trees, forest products, or shade trees; nevertheless the 
families Megachilidae and Xylocopidae sometimes cause light damage. 
| Famity MEGACHILIDAE 
| : Leaf-Cutting Bees 
The bees of the genus A/egachile make their cells out of neatly cut 
pieces of leaves (fig. 196). Leaves cut by these insects are conspicuous 
| and fairly common. Rose leaves are used more frequently than any 
| other kind, but the work of Megachile brevis Say has been reported ** 
as common on both maple and rose in Columbus, Ohio. Megachile sp. 
was reported as very injurious to shade trees in north-central Montana 
in 1932.°° The nests are made in various places. Sometimes holes are 
bored into wood, or a cavity already present is used. Frequently any 
easily adapted place, like a hole in the ground beneath a stone or a 
crevice between shingles, 1s used. 
Famity XYLOCOPIDAE 
Large Carpenter Bees 
Some of the largest known bees are included in the family Xyloco- 
pidae, but most of them inhabit the warmer parts of the United 
States and the Tropics. They tunnel by means of their mandibles into 
the solid wood of beams, rafters, telephone poles, or other structural 
timber, dividing their burrows into a series of cells. These bees de- 
posit a single egg in each cell, which is largely provisioned with pollen. 
Superficially the adults resemble bumble bees, but they are usually 
shiny black and without yellowish or reddish markings. 
The carpenter bee (Xylocopa virginica (Drury) ) is the only spe- 
cies found in the northeastern part of the country. It isa large insect, 
about an inch long, and resembles a bumblebee. It has been reported 
as causing considerable damage in Ohio by boring in exposed beam 
ends in houses, and has been reported from Kansas as boring in garage 
timbers. It sometimes excavates a tunnel a foot in length, which it 
divides into several cells. The partitions between the cells are made 
of chips of wood, securely cemented together and arranged in a closely 
wound spiral. X. orpifex Smith and X. brasilianorum (l.) are 
found in the southwestern part of the United States. The former 
bores in sound redwood and occasionally in Oregon pine, the latter 
prefers partly decayed live oak, pepper, and eucalyptus. Injury to 
cut juniper logs from Arizona by Xylocopa sp. has been illustrated by 
Snyder (fig. 197). Ordinarily, damage done by carpenter bees is of 
little or no consequence, but structural repairs may be necessary if 
colonies are formed year after year in the same timbers. Dwellings 
are usually protected by frequent applications of paint. Dusting 
partially constructed tunnels in wood, either with derris powder (4- 
percent rotenone) or 10-percent DDT powder; or packing them with 
absorbent cotton saturated with carbon disulfide and sealing the en- 
! trance hole with putty, will kill the adult bees and check the damage. 
SS 
*U. S. Dept. Agr., Insect Pest Survey Bul. 9: 256. 1929. [Processed.] 
° U.S. Dept. Agr., Insect Pest Survey Bul. 12: 327. 19382. [Processed.] 
