119 
The only previous mention of this species is contained in an 
article prepared at my request by Mr. Webster, (in my office at the 
time, ) and published in the Bulletin of the Illinois State Laboratory 
of Natural History* in February, 1904. In this article the species 
is described by Chittenden under the name of Obcrea nUnicola, and 
the main facts are reported so far as observed up to that time. 
Rkcognition of the Injury. 
The presence of this insect may be suspected when the tips of 
small twigs of the elm, each bearing a few fresh leaves and cut 
squarely off at the base, fall from the trees between May 20 and 
June 15. A careful examination of the stubs remaining on the tree 
where these twigs have been cut off, will show a narrow encircling 
groove or girdle cut through the bark at two inches or less from 
the blunt end, and a small L-shaped slit between this girdle and the 
end of the stub. On other twigs which have not yet lost their tips, 
two girdling grooves may sometimes be seen, about two inches 
apart, with the L-shaped slit between them, and in this case the tip 
of the twig may be readily broken off at the groove nearest the end. 
If a tree has been considerably infested the preceding year, dead 
stubs, single or clustered, may be seen here and there on the 
branches, with younger twigs springing up among them and still 
alive. Repeated injuries of this description, year after year, give 
the tree a scrubby and unwholesome look, and may even kill it 
eventually, after forcing it to put forth new twigs repeatedly, as 
the growth of the preceding season is destroyed. 
The insect doing this injury is a slender, cylindrical, hard- 
shelled beetle, about half an inch long, with head and body black 
above, except the thorax, which is yellow with two round black 
spots near the middle. The color beneath is mainly yellow. 
(PI. VIII. , Fig. a.) The female lays her eggs, one in a place, 
usually under a triangular flap of bark made by the intersection of 
the lines of an L-shaped slit. 
The slender larva of this beetle (Fig. c) lives within the injured 
twigs, which it burrows lengthwise, pushing its excrement out 
through small round holes made in the bark for the purpose. It is 
about half an inch long when full grown, light straw-colored, a lit- 
tle darker at the ends. The pupa (Fig. d) \s formed in the larval 
burrow. 
*VoI. VII., pp. 1-13. 
