58 INSECTS INJURIOUS TO FOREST AND SHADE TREES 
INSECTS INJURIOUS TO THE ELM. 
AFFECTING THE TRUNK. . 
1. THE COMMON ELM-TREE BORER. 
Saperda tridentata Olivier. 
Order COLEOPTERA; family CERAMBYCID&. 
Perforating and loosening the bark and furrowing the surface of the wood with 
‘their irregular tracks, flat white longicorn borers, changing to beetles in June and 
July; the beetles flat, dark brown, with a longitudinal three-toothed red stripe on 
the outer edge of each wing-cover. 
This is the most destructive borer of the elm in the Northern and 
Eastern States, often killing the trees by the wholesale. Great num- 
bers of the larve of different sizes have been found boring in the inner 
bark and also furrowing with their irregular tracks the surface of the 
wood, the latter being, as it were, tattooed with sinuous grooves, and the 
‘tree completely girdled by them in some places. The elms on Boston 
Common have in former years been killed by this borer, and valuable 
trees, we have been informed, have been killed by them in Morristown, 
N. J. Fitch remarks that it consumes the inner bark of the slippery 
elm (Ulmus fulva), especially in dead and decaying trees. According 
to him, ‘the beetle deposits its eggs upon the bark in June, and the 
young larvie therefrom nearly complete their growth before winter, and 
Soon after warm weather arrives the following spring they pass into 
their pupa state.” We have found the larvee in abundance in the early 
spring in Providence in old dead elms. 
The larvaa—White, subcylindrical, a little flattened, with the lateral fold ot the 
body rather prominent; end of the body flattened, obtuse, and nearly as wide at the 
end as at the first abdominal ring. The head is one- 
half as wide as the prothoracic ring, being rather large. 
The prothoracic segment, or that next to the head, is 
transversely oblong, being about twice as broad as 
long; there is a pale dorsal corneous transversely ob- 
long shield, being about two-thirds as long as wide, 
and nearly as long as the four succeeding segments ; 
this plate is smooth, except on the posterior half, which 
is rough, with the front edge irregular and not extend- 
ing far down the sides, Fine hairs arise from the front 
ic. 17,--Tarva (from Hife) ‘and adult edge and side of the plate, and similar hairs are scat- 
of the elm-tree borer.—F rom tered over the body and especially around theend. On 
meek gre. the upper side of each segment is a transversely oblong 
ovate roughened area, with the front edge slightly convex, and behind slightly areu- 
ate. On the under side of each segment are similar rough horny plates, but arcuate 
in front, with the hinder edge straight. 
It ditrers from the larva of Saperda vestita Say in the shorter body, which is broader, 
more hairy, with the tip of the abdomen flatter and more hairy. The prothoracic seg- 
‘ment is broader and flatter, and the rough portion of the dorsal plates is larg>r and 
Less transversely ovate. The structure of the head shows that its generic distinctness 
