18 SEVENTEENTH Report STATE ENTOMOLOGIST OF Minnesota—1918 
Fig. 3. An oak tree showing dead limbs killed by the oak twig girdler. 
measured 0.75 millimeters, which is the head measurement of the 
mature larvae. 
During October many of the larvae began coming out from the 
center of the twig and encircling it just beneath the bark. Burrows 
five and six inches long were often found before this occurred. Often 
the side branch on which they were working was not long enough and 
the encircling of the branch would take place on a main branch. Note 
