2 BULLETIN 766, U. S. DEPARTMENT OF. AGRICULTURE. 
setts, that enormous areas of forest and shade trees were defoliated | | 
annually. In some residential sections life was rendered almost un- 
bearable by the presence of enormous numbers of caterpillars. A1- 
though the history of the introduction and destructive work of these 
two pests has already been published, few except eye witnesses could 
realize the serious conditions that existed at the time parasite intro- 
duction was begun. 
Since 1891, when the gipsy moth covered an area of approximately 
200 square miles, it has spread until in 1916 it involved 20,715 square 
miles, and is found in all of the New England States. In some 
localities in Massachusetts, where it was once accounted a plague, the 
severity of the infestation has been reduced to such an extent that 
the pest is more easily controlled. 
The brown-tail moth was first regarded as a serious problem in 
1897, when it was found in 15 towns close to Boston. Since then it 
has spread until now (1916) it covers a territory of 38,118 square 
miles, occurring in all of the New England States. Both sexes of the 
brown-tail moth are strong fliers. This important factor helps to 
explain why this insect is found over a larger area than the gipsy 
moth, the female of the latter species being unable to fly. 
The life cycle of both the gipsy moth and the brown-tail moth is 
such that all stages, with the exception of the imago, are attacked by 
parasites. The internal-feeding parasite Compsilura concinnata is 
parasitic only upon the larve of these two hosts, and, while it has 
been reared occasionally from the pup, it will not complete its life 
cycle if the attack is delayed until the host pupates. These two hosts 
form an ideal combination for Compsilura, as the brown-tail moth 
larvee occur in the field a short while after the parasite emerges from 
1“ Insect Life,” Vol. III, p. 297. 
“Wifth Report of Entomological Commission,” A. S. Packard, 1890, p. 138. 
“The Gipsy Moth,” Forbush and Fernald, 1896. State of Massachusetts. 
“The Gipsy Moth in America,’ Bureau of Ent. Bull., New Series, No. 11, 1897. 
“The Brown-tail Moth,” Fernald and Kirkland, 1903. State of Massachusetts. 
“Report on the Gipsy Moth and Brown-tail Moth,” C. L. Marlatt, Bureau of Ent. Cire. 
No. 58, 1904. 
“A Record of Results from Rearings and Dissections of Tachinidae,’ Townsend, Bureau 
of Ent. Bull. Tech. Series No. 12, Part VI, 1908. 
“ Parasites of the Gipsy and Brown-tail Moths Introduced into Massachusetts,” W. F. 
Fiske, 1910. State of Massachusetts. 
“Report on Field Work Against the Gipsy and Brown-tail Moths,” Rogers and Burgess, 
Bureau of Ent. Bull. No. 87, 1910. 
“The Importation Into the United States of the Parasites of the Gipsy Moth and the 
Brown-tail Moth,’ Howard and Fiske, Bureau of Ent. Bull. 91, 1911. 
“The Gipsy Moth as a Forest Insect, with Suggestions as to its Control,’ W. F. Fiske, 
Bureau of Ent. Cire. No. 164, 19138. 
“The Dispersion of the Gipsy Moth,’ A. F. Burgess, Bureau of Ent. Bull. No. 119, 
19138. 
“The Gipsy Moth and the Brown-tail Moth, with Suggestions for their Control,” A. F.. 
Burgess, Farmers’ Bull. No. 564, 1914. 
“Report on the Gipsy Moth Work in New England,” A. F. Burgess, Dept. of Agri. 
Bull. No. 204, 1915. 
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