33 
The winged insects are readily distinguished by a comparison of 
the wings and abdomens. In triciuctiis (Fig. 35) the fore wings 
are violaceous-black, the hind wings are transparent, and the ab- 
domen is black with three or four yellow bands. In dollii (Fig. 
36) the fore wings are brown, the hind wings are brown and 
Fig. 31. Poplar Borer 
31e7nythrus tricinctus or 
dolii, egg. Greatly en- 
larged. 
Fig. 
12. Poplar Borer, Memythrus dollii, larv'a. 
About 3 times natural size. 
opaque, except at the base, and the abdomen is brown, sometimes 
with one or more yellow bands. 
In our work with these borers it was not at first known that two 
species were concerned, and the larv?e were not distinguished in our 
notes. It was only when the adults appeared that the specific dis- 
tinctions were established. 
Pig. 33. Poplar Borer, 
Memythrus tricinctus or 
M. dollii, pupa. About 
3 times natural size. 
Fig. 34. Poplar Borer, 
Memythrus tricinctus or M. 
dollii, anal end of pupa. 
Greatly enlarged. 
