47 
half of June, eats its way thru this terminal twig, and feeds dur- 
ing its short life on the leaves of the infested tree, making oval 
holes thru the leaves along the course of the veins. (Fig. 53.) 
The presence of this borer is commonly first betrayed by a with- 
ering of the leaves at the tip of the girdled shoots. It is a rather 
common pest in the Chicago parks, where it has often been abun- 
dant enough on the red-osier dogwood (Cornus sanguvica) to be 
decidedly injurious. Like the other small twig-girdlers, this species 
can best be destroyed by cutting off and destroying the affected 
/^ 
Fig. 52. Dogwood Twig- 
girdler, Oberea tripunctata, 
pupa. About ZVn times 
natural size. 
Pig. 53. Cornus leaf injured by- 
feeding of adult Dogwood Twig', 
girdler, Oberea tripunctata. 
branches at a time when they are certain to contain the borer ; that 
is to say, in this case, in any month except June and July. 
The various species of this genus have been so imperfectly dis- 
tinguished that a specific description of this will not be attempted 
here; but the reader is referred to the illustrations for its general 
characters. Its larva is much subject to destruction by parasites; 
and a characteristic parasitic species has been repeatedly bred by 
us from infested twigs. 
