Family Sesiidae 
Clearwing Moths 
Members of this family are known as clearwing moths because the greater part of 
one or both pairs of wings are without scales, thus leaving them clear or trans- 
parent. The forewings are long and narrow, with the outer margins short and the 
anal veins reduced. The hindwings are somewhat broader than the forewings, and 
the anal areas are well developed. In some species, the two sexes are colored 
differently. Many species bear a striking resemblance to bees or wasps. The adults 
are swift fliers and are most often seen around flowers. The larvae are ivory-white 
and mostly unmarked. They bore in the roots and basal stalks, the trunks, or 
branches of trees, shrubs, and vines, or in the stems and roots of herbaceous plants. 
A few form galls, others are inquilines in galls, and some inhabit injured areas on 
the trunks or branches of their hosts. A number of species are important pests of 
forest and shade trees and ornamentals. The family is discussed (345, 354, 795). 
The hornet moth, Sesia apiformis (Clerck), an introduced species first observed 
in North America around 1880, is now known to occur in Massachusetts, Connecti- 
cut, New York, New Jersey, Pennsylvania, and California. [ts hosts are poplar and 
willow. The larvae bore in the roots, trunks, or large limbs. The adult is brownish 
black except for yellow markings on the head and sides of the thorax; it has a 
wingspread of 34 to 44 mm. It also has black and yellow bands on the abdomen, 
and brown legs. Because of its close resemblance to the giant hornet, it is known as 
the hornet moth. Full-grown larvae are white with reddish heads and are about 30 to 
50 mm long. They excavate extensive tunnels in their hosts, causing swellings to 
occur. Young trees are often killed. Two years are required to complete the life 
cycle. The first winter is spent in the larval stage in the wood; the second, as a larva 
in a cocoon in wood borings in or close to the base or roots. 
Sesia tibialis (Harris), the poplar clearwing moth, attacks poplar and willow 
from New York to Nova Scotia westward across the Northern States and southern 
Canada to the Pacific Coast and southward to California. Adults are distinguished 
_ by their black abdominal segments, of which all but the second and fourth have 
narrow posterior yellow margins. Full-grown larvae are 40 mm or more long. 
Infestations are located well down on the trunk or in the roots. 
The dogwood borer, Synanthedon scitula (Harris), occurs in southeastern Can- 
ada and throughout the eastern half of the United States. Although normally a bark 
borer in oaks, it also attacks a wide variety of other deciduous hardwood trees, 
shrubs, and sometimes pine. It is often an important pest of flowering dogwood and 
pecan. In the South, it is commonly called the pecan borer. Abnormal growths such 
as woody galls, excrescences due to fungi, rusts, blight, and bruises and healing 
wounds are attractive as points of attack. Galls, such as those produced by the 
cynipid Callirhytis cornigera (Osten Sacken) on black and pin oaks, sometimes 
occur in the thousands on a single tree, and nearly every one will be infested by this 
borer (354). 
The adult is a small, blue-black moth with yellow-banded legs and yellow stripes 
on segments two and four of the abdomen. The wings are transparent with blue- 
black margins, and the wingspread is from 14 to 20 mm. The larvae are whitish 
with brown heads and are up to 14 mm long. 
Eggs are laid from late spring to midsummer on rough bark or around wounds. 
The larvae enter the bark through openings and feed in the cambial area. Infested 
areas are sometimes up to 61 cm or more in length and may contain up to SO larvae 
each on the larger trees. A single larva can kill a dogwood 10 cm in diameter in | 
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