their extremely long ovipositors, the females bore deep holes into 
the wood and deposit their eggs on or near horntail larvae in 
their galleries. 
Horntail adults are medium to large in size and are usually 
metallic blue or black in color. Some are vari-colored with com- 
binations of black, red, and yellow. The head, thorax, and ab- 
domen are of equal width; the wings are well developed; the an- 
tennae are long and filiform, with about 15 segments; and the 
anterior tibia is armed with a single apical spur, cleft at the 
apex. 
Damage caused by members of the family can be prevented or 
reduced by the prompt utilization or submersion in water of in- 
fested logs and by kiln drying of green lumber sawed from in- 
fested logs. 
The genus Sirex L. is represented by four eastern species. S. 
juvencus (L.) occurs in eastern Canada and the Northeastern 
and Midwestern States. Its hosts are listed as pine, fir, and spruce. 
S. abbottw Kirby has been recorded breeding in larch in New 
York and Georgia. The blue horntail, S. cyaneus F., attacks spruce 
and pine in southern Canada and the northern tier of eastern 
States. S. edwardsi Brulle has been taken from pitch pine in the 
Atlantic Coast States. S. nigricornis F. attacks shortleaf pine 
from New York to Ohio and Florida. 
The genus Urocerus Geoffrey is represented by three eastern 
species. U. albicornis (F.), the white-horned horntail, attacks many 
species of conifers and occurs throughout boreal America. Adults 
are blue-black or black and about 25 to 30 mm. long. The middle of 
the antennae, cheeks, bases of the tibiae, and tarsi are white. White 
spots also occur at times on the sides of the abdomen. This spe- 
cies has also been observed attacking freshly sawed lumber. U. 
flavicornis (F.), the yellow-horned horntail, attacks spruce and 
other conifers in New England and Canada. Adults are black 
and from 20 to 37 mm. long. Females have the first, sixth, and 
part of the seventh abdominal segments yellow; males have the 
second through fifth segments orange-yellow. U. cressont Norton, 
the black and red horntail, occurs from eastern Canada to Georgia 
and breeds in poplar. 
The pigeon tremex, Tremex columba (L.), is the most common 
of the horntails. It occurs throughout nearctic America and breeds 
in a wide variety of dead or weakened deciduous trees such as 
beech, maple, birch, elm, hickory, oak, and sycamore. The adult 
female is 37 to 50 mm. long. The head, antennae, and thorax are 
reddish and black; the abdomen is black with ocher yellow bands 
and spots along the sides; and the wings are smoky brown with 
an expanse of 50 mm. or more. Males are reddish, with some 
black, and are about 18 to 37 mm. long. Full-grown larvae are 
whitish, cylindrical, and about 50 mm. long. The abdomen ends 
in a short, strongly sclerotized and compressed process armed 
with two pairs of small teeth. 
The female bores through the bark to a depth of about 12 mm. 
in the wood to deposit her eggs. Although laid singly, several 
eggs may be found near each other in a limited area. The larvae 
feed by excavating tunnels entirely in the wood. This frequently 
weakens the tree and leads to wind breakage. Pupation occurs at 
466 
