29 
rowing in spring, but pupate in April or the first part of May. As 
a preparation for pupation, they burrow outward and cut their 
way thru the bark, leaving only a thin outer film to close the pupal 
cavity. By means of short teeth with which each segment of the 
abdomen is armed, the pupa, when mature, works its way out of 
Fig. 2S. Lilac Borer, Podo- 
sesia xyri/igie, larva. About 
5 times natural size. 
Fig. 27. Lilac Borer, Pod- 
osesia syringce. Burrows 
in ash made by larvae. 
Slightly reduced. 
its gallery until it projects some three-quarters of an inch. The 
winged insects, altho moths, closely resemble wasps in movement, 
color, and form. They make their appearance from the latter part 
of April to the middle of June in central and northern Illinois. 
The borer or larva (Fig. 28) is very variable in length. It is 
white, yellowish anteriorly, the head of a bright mahogany color, 
becoming very dark at the mandibles, which are stout, broad, and 
provided with five teeth. The segments of the body are distinctly 
