FAMILY DIPRIONIDAE 
CONIFER SAWFLIES 
The family Diprionidae includes many of the most serious de- 
foliators of conifers. The majority of species are native to the 
continent but several of foreign origin are well established. The 
family is divided into two subfamilies, Monocteninae and Dipri- 
oninae, and five genera (550). Adults are described as follows: 
Antennae composed of 18 or more segments, serrate in the female, 
and pectinate or bipectinate in the male. Mesosterno-plural su- 
tures atrophied, mesoscutellum with anterior margin V-shaped, 
posterior margin with an exremely narrow and cordlike poster- 
gite (621). The larvae usually range in length from about 18 to 
25 mm. The body is usually whitish, yellowish or grayish with 
brown or black stripes or rows of more or less distinctly separated 
spots (801). 
Many species of diprionids are serious pests in both forest 
stands and plantations. Outbreaks occur periodically, sometimes 
over extensive areas, resulting in loss of growth and sometimes 
tree mortality (11, 160). 
The genus Monoctenus Hartig is represented in the United 
States and Canada by four species, all of which occur in eastern 
America on Juniperus. None are considered serious pests of forest 
or shade trees. M. melliceps (Cresson) occurs in southern Canada 
and in the Northeastern States west to Kansas. Its hosts are red 
cedar, arborvitae, and juniper. Full-grown larvae are dull green 
and about 18 mm. long. The head is light brown; the body is 
marked with three dark longitudinal stripes; and the legs are 
black. Adults appear in May, and larvae are active during June 
and July. | 
The genus Neodiprion Rohwer contains many of the most de- 
structive species of sawflies. During recent years outbreaks of 
several species have occurred, resulting in serious damage to 
young pines on thousands of acres of pine plantations in eastern 
United States. Some outbreaks spread over millions of acres of 
forested areas before subsiding. Atwood and Peck (12) and Ross 
(623) discussed the taxonomy of the genus and Krombein (442) 
published a check list of North American species. 
The red-headed pine sawfly, Neodiprion leconter (Fitch), occurs 
in southeastern Canada and throughout eastern United States. Its 
preferred hosts are jack, red, shortleaf, loblolly, slash, longleaf, 
pitch, and Swiss Mountain pines. White pine, larch, deodar cedar, 
and Norway spruce may also be defoliated, especially where they 
are growing close to trees of preferred species. Full-grown larvae 
are about 22 to 25 mm. long. The head is reddish and the body is 
yellowish-white, with six rows of black spots (fig. 176). 
Winter is spent in the prepupal stage. Pupation occurs in early 
spring and the adults appear in a few weeks. Eggs are deposited 
in the tissues of current or previous year’s needles, a single female 
depositing up to 100 eggs. The larvae feed gregariously on new 
and old needles and usually completely defoliate one branch be- 
439 
