70 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
impractical to make a very fine distinction in the insects or in over- 
lapping types of injury, and some judgment and patience must be exer- 
cised in looking for the name of a specimen under a slightly different 
heading, if the first attempt does not seem to answer the problem. For 
example, to separate the leaf miners of the beetles, moths, and sawflies 
would require almost the entire replication of the respective keys under 
these orders; consequently, it seems more simple to refer to all three 
groups. 
The three main divisions used as a primary breakdown aim to group 
the insects according to well-marked fields in the forestry profession ; 
namely, nursery practice, the forest, and the lumbering industry. Ben- 
eficial forest insects, including predators and parasites, and insects 
serving as fish and game food or attacking wildlife are not considered 
in these keys, even though they are discussed to some extent in the text. 
These principal divisions are as follows: 
Insects injurious to seeds, seedlings, young plantations, and small 
TEPLOCUCUOMN A csc a ee eae ee eae oT Division A. 
Insects injurious to larger reproduction, forest trees, and shade 
trees Be See ae te on cameras BE DR NS eh Se Oe ei en Division B. 
Insects injurious ‘to forest. products2 22a Ee See ne ee Division C. 
These main divisions are again subdivided to other groups or sub- 
divisions as shown in the next outline of headings. 
PRIMARY DIVISIONS OF KEY 
A. Insects injurious to seeds, seedlings, young plantations, and small repro- 
duction 
To seeds, cones, and fruits A ee Aa fe er Soy PERS Ee ee See a Io al @ 
Tor seedhingseandasmallsre proc Gti @ rasa eee ee eee eee 7-11 
B. Insects injurious to large reproduction, forest trees, and shade trees 
Acarina-y(red Spiders) <5 22 cee ee Ee. 2 Se ee 1 
Defoliators eat ERS Set Cie eae 2-6 
TL Wigsaid tip amas; sel Cir. eek Oe a ee 7-14 
Borers ans wood, and barks] ss 2s See Se 15—=23 
Gallsswellingss ete, 2222 = rae oe eS eee Se ea eee ey 
Sucking-7inSecis=22—= ae Se = Se ESS eS a ee a 32-35 
C. Insects injurious to forest products 
Defects in green timber_______--_ ee etl oe fe 1-5 
Insects in round logs__—_____ sagen ERS Se pe eo acer eg ee are eee oP 6 
Insects in lumber____~— = = Sue ie ae Jats STE al) 
Insects in material in eround pen Bev Tea hee Be ae Be Ree ae 11 
Defects in wood in salt and brackish water, marine borers________ 12 
DIVISION A 
INSECTS INJURIOUS TO SEEDS, SEEDLINGS, YOUNG PLANTATIONS, 
AND SMALL REPRODUCTION 
This group includes the insects that attack the fruit and seeds of 
forest trees and the young plants in the nursery or forest. After the 
plants have become 4 or 5 years old, or more or less shrubby or woody, 
they are considered under Division B. This distinction between A and 
B is artificial but convenient. 
™ The numbers given in this column refer to those to be found at the left margin 
in the respective keys that follow. 
