INSECT ENEMIES OF EASTERN FORESTS Do 
neath which is a double row of black spots, the latter sometimes ob- 
solete. It occurs in the northeastern part of the United States and 
feeds on pitch pine. Its life cycle is similar to that of the red-headed 
pine sawfly. 
Data on two additional species of Neodiprion found in Canada have 
been supplied by A. W. A. Brown, of the Canadian Department of 
Agriculture. It seems probable that these may also occur in the States 
bordering Canada. The larva of WV. dubiosus Sched] has a brown 
head, and the body is heavily striped. It overwinters in the cocoon. 
It feeds on jack pine from Saskatchewan to New Brunswick. The 
larva of WV. swainei Midd. has a brown head and the body is lightly 
striped. It feeds on jack pine in Ontario and Quebec. 
The larva of the introduced pine sawfly (Diprion simile (Htg.) ) 
(fig. 150) is about 1 inch in length, the head is black, the body yellow- 
ish green with a double stripe of black down the back, and the sides 
of the body are mottled with yellow and black. 
This European insect was first discovered in this country in Con- 
necticut in 1914. It is now rather well distributed through the North- 
eastern States and apparently is most common on ornamental pines. 
Specific records of occurrence include Maine, Massachusetts, Con- 
necticut, New York, New Jersey, Pennsylvania, Virginia, District 
of Columbia, and Indiana. It has been reported also from the 
vicinity of Montreal and Toronto, Canada. White pine (Pinus stro- 
bus) and other five-needled pines are preferred as food, but records 
show that the softer two-needled pines are also suitable food plants. 
It is a vigorous defoliator, and apparently the most serious infesta- 
tions have been in ornamental plantings of pine and in nurseries, 
The seasonal history of this insect is rather complicated, as there 
may be one or two generations, or one and a partial second genera- 
tion, annually. The cycle from adult to adult may be about 2 months 
oras long as 12 months. Adults may emerge from cocoons from April 
to September. Records show that this species may reproduce 
parthenogenetically, but when it does the progeny are always males. 
The eggs are laid in slits cut in the needles of the previous season’s 
growth, and they hatch in 8 to 14 days. The young oa vae feed only 
along the edges of the needles, but after they are 9 to 10 days old 
they begin to consume the entire needle. The old foliage i is preferr ed, 
but as the season progresses and the new growth matures it also is 
eaten by the larvae. 
Although larvae may be found from May through September, the 
periods of greatest abundance are in May and June and in August 
and September. The larval stage may be ‘completed i in 16 to 32 days 
depending on the weather. The larvae spin tough white silken 
cocoons, about 54, to %, inch in length, among the needles on the 
twigs or on other parts of the trees or in the litter on the eround, 
The cocoons soon turn brown and blend rather well with their sur- 
roundings. The period spent in the cocoon may range from about 
10 days to almost a year. The winter is passed in the prepupal stage 
in the cocoon (Middleton, 301). In the United States insect para- 
sites, particularly species of Hymenoptera that attack the hibernating 
cocoons, play an important part in the control of this pest. 
The full-grown larva of Diprion frutetorum (F.), prior to the last 
molt, is about 46 inch in length. The ae is reddish brown, 
