138 MISC. PUBLICATION 278, U. S. DEPT. OF AGRICULTURE 
BARE WEEVILS 
Some bark weevils of the genus Pissodes (48) are particularly im- 
portant as enemies of terminal shoots (p. 33) ; others attack the basal 
portion of the trunk of small trees and may extend their work into the 
roots. Weakened, suppressed, and decadent trees are usually preferred, 
but under some conditions these insects may attack healthy trees. 
Usually they breed under 
the bark of logs, in stumps, 
or under the bark of dying, 
standing trees and hence 
are of little economic im- 
portance. 
The adults are stout bee- 
tles with uniform or varie- 
gated markings of yellow, 
brown, or black. The head 
is prolonged into a snout 
or break, which is used to 
puncture buds and tender 
bark of terminal or lateral 
branches for feeding pur- 
poses, and in the case of the 
female to make a hole for 
the reception of the eggs. 
The larvae are small, white, 
legless grubs, with curved 
cylindrical bodies. The 
larvae mine under the bark 
and form winding galler- 
ies, gradually increasing in 
size, which extend through 
the inner bark and some- 
times score the sapwood. 
Each mine ends in a pupal 
cell constructed partly in 
anne ee the bark but mostly in the 
FIGURE 69. Yosemite bark weevil (Pissodes yosem- sapwood, This cell is oval 
a ODk) Typical work and adults. Natural in outline and is lined with 
excelsiorike shreds of 
wood fiber. The nearly round larval mines and the “chip cocoons” 
are characteristic features of their work. 
The adults are long lived and may deposit their eggs over a con- 
siderable period of time. The larvae, which reach maturity rapidly, 
usually within 2 or 3 months, may overwinter in the galleries or 
transform to adults that either overwinter under the bark or emerge 
and hibernate in the ground. There usually is but one generation 
annually. 
Artificial control of the species in western forests has never been 
found necessary, as they are usually held in check by natural enemies 
and the limitation of suitable breeding material. 
Bark weevils of the genus Pissodes that are most commonly found 
breeding under the thick bark at the base of small conifers, and the 
hosts in which they breed are as follows: 
