Keys to the Orders and Families of Forest 
Insects and Allies, Based on Types of Injury 
The following keys are designed for the use of those unfamiliar with the orders 
and families of insects. They are first separated into primary divisions according to 
the portions of trees attacked, the size of the trees, and the timber products infested. 
These main divisions are in turn subdivided into other groups or subdivisions. 
I. 
III. 
Primary Divisions of Key 
Insects injurious to seeds, seedlings, small reproduction, and young planta- 
tions. 
A. Seeds, cones, and fruits. 
B. Seedlings and small reproduction. 
Insects, etc., injurious to large living trees and to small trees more than | or 2 
meters tall. 
A. Yellowing foliage. 
B. Defoliators, leafminers, etc. 
C. Twig and tip damage, etc. 
D. Borers in wood and bark. 
E. Galls, swellings, etc. 
F. Sucking insects. 
Insects injurious to forest products. 
Defects in green timber. 
Insects in round logs. 
Insects in lumber. 
Insects in wood in ground. 
Defects in wood in salt and brackish water. 
SS 
Division I 
Insects Injurious to Seeds, Seedlings, Small Reproduction, 
and Young Plantations 
This group includes the insects that attack the seeds, cones. and fruits of forest 
trees. and young seedlings in the nursery, plantation, or forest. Insects attacking 
trees more than 4 or 5 years old (large reproduction, forest and shade trees) are 
discussed under Dvision II. 
l. 
34 
A. Insects Attacking Seeds, Cones, and Fruits 
Larvae without well-developed head capsule: maggotlike: 
With a sclerotized structure like a “breastbone” near anterior end: in 
seeds of fir, baldcypress. birch, and fruit of chokecherry..... Diptera, 
Cecidomyiidae 
Without “breastbone”: mouth parts well developed: in fruits of cherry. 
apple. plum. hawthorn: in berries of dogwood. holly, and others: and in 
WalnUL IDUSKS: 24 23.6 5c Seen pee et eee eee Diptera. Tephritidae 
i) 
