INSECT ENEMIES OF EASTERN FORESTS Pei 
and, together with the dorsal and ventral pads (ampullae), form an 
efficient device for movement of the larva in its burrow. The tenth 
segment is modified into two or three small retractile (anal) lobes. 
The fleshy appendages on the under side of the head, the ventral mouth 
parts, are never attached far back on the head, and are always about 
on a line with the base of the mandibles. The larvae may or may not 
have small legs. 
CLASSIFICATION OF ROUNDHEADED BORERS BY CHARACTER OF WORK 
The roundheaded borers can be conveniently grouped as follows: 
I. Larvae found girdling twigs or stems. 
II. Larvae found in galls on living plants. 
III. Larvae found boring in the bark proper of living plants. 
IV. Larvae found boring under the bark or in the wood of living trees. 
V. Larvae found in roots of living plants. 
VI. Larvae found beneath bark or in wood of recently dead, dying, or felled 
trees. 
VII. Larvae found in older, moist wood in contact with the ground. 
VIII. Larvae found in dry, seasoned wood, or cat faces or fire scars of living trees 
These sections are further subdivided by characters related to their 
work and also anatomical differences, as will be shown under the 
following subheadings with their more detailed keys. 
KEY TO THE TWIG GIRDLERS 
The twig girdlers sever small twigs or branches from the living 
trees. These branches may be seen hanging in the tree or lying on the 
ground in late summer, fall, or winter. They are severed either by 
the adult insect, which gnaws the bark cleanly through, while the cen- 
tral part of the stem is roughly broken, or by the larvae, which cut 
the twig from within, hollowing out the central part of it, cutting 
the edge off cleanly, and leaving the bark irregularly broken. This 
class also includes certain borers that attack shrubs, such as rhododen- 
dron, sassafras, sumac, seedling oaks, and chestnuts. These larvae 
cut off the twig or stem after they have finished feeding in it and move 
to the lower part of the plant, often to the roots. 
Ks Twigs cut from the outside, never hollowed out at point of sev- 
SUES GS a aT RE ee EY hae ee ee de 2 
Twigs girdled from within, a part of stem always hollow__-_-_____ 3 
2. Egg punctures and feeding scratches on twigs; head of larva 
bearing a transverse row of ridges above______-__- Oncideres 
No evidence of egg scars or feeding scratches; severed twigs 
MEVereeCcOnLAmMIne TATVACSS. 2522 2528 oe ee eee Oberea 
Onesassabrase =e bee ee a ON O. ruficollis, p. 256 
On rhododendron and azaleas__.-...----- O. myops, p. 255 
@On-elm; dogwood, apple_.__....--- O. tripunctata, p. 256 
@intsunmacs:s hae ntanre es De hee O. ocellata, p. 255 
3. iLanvacsroundein girdled portion: 2. .225 5-22 S222 52523-5255 — 25 a 
Larvae boring into green portion of stem, remaining on plant; 
girdled portion having a series (sometimes but a few) holes 
Glnnge wouter kaw ee Cees Bel a ee SS es See Gi 
4, Twigs cut off by spiral incisions; sides of twig not perforated 
VAM TIEN@ | OG es uae seagate Le Leal. ey MDE eerie ee eee 5 
Twigs cut by completely hollowing; twig having a series of small 
holes through bark, usually in a straight line_______-__--__-- 6 
5. Larvae having two ocelli on each side of head; pronotum white, 
Slain papeeee ere eee Ses Se Hypermallus villosus, p. 245 
Larvae having but one ocellus on each side of head; pronotum 
brown and velvety____----Xylotrechus quadrimaculatus, p. 269 
