INSECTS INJURIOUS TO THE LOCUST. 95 
INSECTS INJURIOUS TO THE LOCUST. 
(Robinia pseudacacia.) 
AFFECTING THE TRUNK. 
1. THE LOCUST BORER. 
Cyllene picta (Drury). 
Order COLEOPTERA; family CERAMBYCID #. 
Boring a hole + inch in diameter under the bark and upwards, deep into the wood, 
and ejecting the dust through the orifice in the bark, a longicorn larva, which trans- 
forms to a pupa in its burrow, and late in summer appears as a brown beetle, striped 
and banded with golden yellow, and with a W on its wing-covers; often abundant on 
the flowers of the golden rod early in September, when they lay their eggs in crevices 
in the bark of the locust. 
This is by far the most destructive pest of the locust, one of the most 
beautiful and valuable of our shade trees. In New England there is 
scarcely a tree which does not show the marks of its attacks, and in many 
localities it has practically been exterminated. Inthe Western States it 
is also very destructive; but from observations we have made in Ken- 
tucky the noble locust trees in that State grow so luxuriously as to 
apparently escape or overcome the insidious attacks of this borer. It 
occurs throughout the United States east of the Plains. 
The operations of the grub or larva may be detected by a mass of 
sawdust-like castings at the mouth of its gallery. 
The beetles are abundant, feeding on the flowers of the golden rod 
(Solidago), early in September, when we have taken them in Cambridge, 
Mass., and Providence, R. I. So wide are the deep yellow spots and 
bands that the beetle is nearly all of the shade of deep golden yellow 
peculiar to the flowers of the golden rod, and thus the insect is an 
interesting case of ‘protective mimicry,” being protected from the 
attacks of birds, &c., by its liability to be confounded with the yellow 
heads of the golden rod. 
The best account of these insects has been given, as follows, by Harris: 
In the month of September these beetles gather on the locust-trees, where they may 
be seen glittering in the sunbeams with their gorgeous livery of black velvet and gold, 
coursing up and down the trunks in pursuit of their mates, or to drive away their 
rivals, and stopping every now and then to salute those they meet with a rapid bow- 
ing of the shoulders, accompanied by a creaking sound, indicative of recognition or 
defiance. Having paired, the female, attended by her partner, creeps over the bark, 
searching the crevices with her antenne, and dropping therein her snow-white eggs, 
in clusters of seven or eight together, and at intervals of five or six minutes, till her 
whole stock is safely stored. The eggs are soon hatched, and the grubs immediately 
burrow into the bark, devouring the soft inner substance that suffices for their nourish- 
ment till the approach of winter, during which they remain at rest in a torpid state. 
In the spring they bore through the sap-wood more or less deeply into the trunk, the 
general course of their winding and irregular passages being in an upward direction 
