THE FALL WEB-WORM. oo 
sent us a specimen of a species of Tetrastichus which is probably para- 
sitic upon one of the Pteromali. Further characterization of these 
species we defer to another occasion. 
GEOGRAPHICAL DISTRIBUTION. 
This species is widely distributed in North America east of the more 
timberless regions of the West, extending northward as far as Canada 
and southward well into the Southern States. It is most abundant in 
the Middle and New England States, but it is a noticeable fact that 
wherever it occurs it is more frequent within our cities, or in gardens 
and orchards near by, than in the woods remote from human habitation. 
THE FALL WEB-WORM. 
(Hyphantria cunea, Drury.) 
‘This insect has from time to time attracted general attention by its 
great injury to both fruit and shade trees. Many authors have written 
about it, and consequently it has received quite a number of different 
names. The popular name ‘ Fall Web-worn,’ first given to it by Harris, 
in his ‘Insects injurious to Vegetation,’ is sufficiently appropriate as 
indicating the season when the webs are most numerous. The term is, 
however, most expressive for the New England and other Northern 
States, where the insect is single-brooded, appearing there during Au-, 
gust and September, while in more southern regions it is double- 
brooded. In our Third Missouri Report we have first called attention 
to its double-broodedness at Saint Louis, and we find that it is invari- 
ably two-brooded at Baltimore and Washington. Except in seasons of 
extreme increase, however, the first brood does no widespread damage, 
while the fall brood nearly always attracts attention. 
“We have decided to call attention to this insect somewhat in detail 
in this report, because of its exceptional prevalence and injury in the 
Atlantic States during the year 1886, and because it became a public 
nuisance in the city of Washington, and the District Commissioners 
have formally requested information from us on the subject.” 
NATURAL HISTORY. 
Limitation of Broods.—“ At Washington we may say in general that 
the first brood appears soon after the leaves have fully developed, and 
numerous webs can be found about the first of June, while the second 
brood appears from the middle of July on through August and Sep- 
tember. In Massachusetts and other Northern States the first moths 
issue in June and July; the caterpillars hatch from the last of June 
17527—Bull. 10-——3 
