Superfamily Apoidea 
Bees 
It has been estimated that more than 3,500 species of bees in 7 families occur in 
North America. Some Apidae such as the honey bee and bumble bee, are so 
common as to require no description. Fortunately, none of these insects is particu- 
larly injurious to forest or shade trees. On the contrary, as a group they are highly 
beneficial because of the prominent role so many of them play in the pollination of 
flowers. While the majority of species provision their nests with pollen and honey, a 
few lay their eggs in the cells of other bees where their young live as inquilines or 
parasites and feed on food stored by their hosts. Members of the superfamily are 
distinguished by the following characteristics: the pronotum does not extend back to 
the tegulae, the trochanter is single-jointed, the hind basitarsi are dilated or 
thickened, and the head and thorax are covered with branched hairs. 
Family Megachilidae 
Leafcutting and Mason Bees 
Leafcutting and mason bees are small to medium size and black, blue, brown, 
gray, metallic, or purplish. Some are marked with yellow. They build their nests in 
rotten wood, in holes in solid wood, and in the hollow stems of plants, and they line 
the walls of their cavities with mud, resin, or circular or oval-shaped pieces of 
leaves cut from various species of plants. A few species have been recorded 
damaging shade trees and ornamentals in various parts of the country; otherwise, 
the group is noninjurious. 
Family Anthophoridae 
Digger, Carpenter, and Cuckoo Bees 
The family Anthophoridae is represented by more than a thousand species in the 
United States and Canada. It has been divided into three subfamilies—An- 
thophorinae, Xylocopinae, and Nomadinae. 
The subfamily Anthophorinae contains the so-called mining or digger bees and 
the cuckoo bees. A number of species collect pollen and nest in the ground. Certain 
others, such as the cuckoo bees or Nomadinae, are parasitic in the nests of other 
bees. The adults are usually wasplike in appearance. Members of the subfamily 
Xylocopinae construct their nests in wood or plant stems and are commonly known 
as carpenter bees. The genus Xylocopa contains the large carpenter bees. The adults 
look like bumble bees but differ in having the dorsum of the abdomen largely bare. 
They nest in solid wood. 
Considered as a whole, members of the family are far more beneficial than 
harmful. Many species are highly efficient plant pollinators, and the only destruc- 
tive members of the family are the carpenter bees, several species of which attack 
and damage wood in use. 
The carpenter bee, X. virginica (L.), is an important pest because of its habit of 
tunneling into the solid wood of beams, rafters, telephone poles, or structural 
timbers. This activity may lead to structural damage, especially when the same 
piece of timber is attacked for several years. Dead but sound wood of baldcypress, 
thuja, eastern white and hard pines, and redwood seems to be preferred. The adult, 
which is about 25 mm long, bores a hole about 9 mm in diameter straight into the 
wood for a short distance, then makes a right-angle turn and follows the grain of the 
wood for a distance of 15 to 20 cm. Sometimes two bees use a common entrance 
hole. When this happens the tunnel is extended in opposite directions from the 
entrance hole. Eggs are deposited singly in separate chambers in the tunnel, each of 
which is largely provisioned with pollen. Each larva lives and feeds in its chamber 
until mature. Adults feed on pollen during daylight hours. Females spend the night 
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