MISSOURI BOTANICAL GARDEN BULLETIN 53 
same ordinance it is the special duty of the police to enforce 
this particular section. Everyone, therefore, who sees trees 
being injured by horses or other agencies, should report same 
to the nearest policeman. A vigorous enforcement of this 
ordinance would do much to increase the respect for shade 
trees in the city. 
BORERS. 
Probably the most serious enemy of shade trees is the 
maple borer, which attacks all species of maples. A recent 
examination made of a number of trees in the western part 
of the city showed evidence that: practically every maple 
tree in a stretch of about ten blocks had been attacked by 
this insect. In a recent report on this borer, Dr. Felt, of 
the New York State Department of Entomology, says: 
“While other pests cause much injury, the fact remains that 
the sugar maple borer (Plagionotus speciosus Say) is quietly 
and unobtrusively carrying on its deadly work, and in a 
series of years probably kills more of these popular shade 
trees than any other insect pest.” According to Dr. Felt, the 
maple borer attacks trees in full vigor. He says: “The 
powerful legless grub confines its operations largely to the 
inner bark and sap wood, and as it runs a burrow several 
feet long in one season, and as one borer will frequently 
work transversely half around a tree some eighteen inches 
in diameter, the dangerous character of this pest is at once 
apparent.” The parent insect is a beautiful stout beetle 
about one inch long. It is black, brilliantly marked with 
yellow. The insect lays its eggs in the period from June 
until August, the favorite place for depositing them being 
near the base of the limbs. ‘The young borer starts work 
during the early fall and passes the winter in a shallow ex- 
cavation in the sap wood. In the second year the borer 
works extensively, building burrows in an irregular way 
up and down and around the tree. When the borer is about - 
sixteen months old, it rnakes a deeper hole, and in this hole 
transforms to the pupa and then to the beetle. Where two 
or three borers are working in a tree, they very frequently 
girdle the tree entirely, resulting in its rapid death. The 
burrows of the insect can usually be recognized as slight de- 
pressions on the surface of the trunk. In St. Louis the borer 
is especially active on young maple trees. Plate 10 shows 
ate of the trunks of two trees; the left hand one, planted 
ast year, with several marked burrows; the right hand one 
an older tree in which the serious injuries due to the borer _ 
are beginning to heal over. The only practical way of com-— 
