INSECT ENEMIES OF WESTERN FORESTS 



97 



worms, inchworms, or measuring worms. Adults are medium- 

 sized, slight-bodied, and light-colored moths of which the hemlock 

 looper and the oak looper are typical examples. 



The hemlock looper (Lambdina fiscellaria fiscellaria (Guen.)) 

 (157) is a very destructive defoliator in the spruce, hemlock, and 

 balsam fir forests of the Northeastern States, through Canada, 

 the Lake States, and along the northwestern coast. At intervals it 

 appears in great numbers, strips the needles from trees over large 

 areas, and kills them. These defoliated trees become very dry, and 

 soon form jungles of fallen trees and broken tops, which are fre- 

 quently swept by disastrous fires. 



A subspecies of Lambdina fiscellaria that destroys the spruce- 

 hemlock forests along the coast of Oregon, Washington, and 

 British Columbia is lugubrosa Hulst (fig. 39) (77, 135). During 

 the last 60 years it has figured in four or five major outbreaks and 

 several minor ones. In the earliest outbreak recorded, about 1889 

 to 1891, a vast amount of timber in Tillamook and Clatsop Coun- 



FlGURE 39. — The hemlock looper {Lambdina fiscellaria lugubrosa) : A, Larvae 

 on branch; B, pupae; C, adult moth. Natural size. 



