264 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
pointed. The posterior part of the pronotum is covered with coarse 
recurved asperities and never bears the two dark oblique impressed 
lines, as Oberea (p. 255). ‘The ampullae also Lear fine erect asperities. 
They are legless. A number of these species are of considerable eco- 
nomic importance. They can be recognized as adults by the color 
pattern and as larvae by the host plant and their work. 
The poplar borer (Saperda calcarata Say) is from 21 to 30 mm. in 
length, reddish brown, and densely clothed with gray and yellow 
pubescence. It has three yellowish stripes on the thorax and lines 
and blotches of orange yellow on the elytra. The larva (fig. 56, 4) 
feeds in the trunks of living poplars throughout the United States. 
In early to late summer, according to the. locality, the adults fly and 
feed on the bark of the young twigs or leaf bases. The female gnaws 
an oval hole through the bark in which one or two eggs are inserted. 
In about 3 weeks fie young larva hatches and extends its mines be- 
neath the bark. Not until the next season does it enter the wood, in 
which it continues to’ feed until matured. The fibrous frass is exuded 
in large quantities from a hole marking the point of oviposition. This 
hole is enlarged as the larva grows, and thr ough it the adult emerges. 
The pupal cell is at the end of the gallery in the wood and is plugged 
beneath by a wad of fibrous frass. Three years is required to complete 
the life cycle. 
Hofer (227) considered this one of the most serious pests of poplars. 
Small ue are often killed by the larvae girdling beneath the bark, 
but greater damage results from the decay in the abandoned mines 
and the breaking off of the trees where the heartwood has been weak- 
ened. Poplar plantations have been totally ruined. Shade trees also 
suffer severely. Almost all species of poplars have been found to be 
attacked by this insect, but a variety of the common cottonwood of 
the Mississippi Valley seems to be immune. For control see pages 
24-26. 
The roundheaded apple tree borer (Saperda candida F.) is about 
20 mm. long, of a brownish color striped above for the entire length 
of the body with two bands of white meeting at the front. The an- 
tennae are gray and the under side of the body i is white. The larvae 
feed in the wood at the base and roots of living serviceberry, thorn 
apple, mountain-ash, and many fruit trees in the eastern part of the 
United States. 
Early in the summer the adults fly and deposit the eggs in small 
scars gnawed at the bases of the trees. The larvae feed “beneath the 
bark for a year, then bore into the wood, making large excavations, 
riddling the base, and exuding much fibrous frass. Two, or more years 
are required to complete the development. The adult gnaws an exit 
hole above the point where frass was exuded. 
In the forests this insect cannot be considered of great importance 
because of the shght value of the trees in which it feeds. In orna- 
mental plantings ‘and orchards, however, where they are of greater 
value, these plants are frequently attacked and killed, or the base may 
be so riddled that the trees are broken off by the wind. Control meas- 
ures are indicated on page 24. 
Saperda concolor Lec., the poplar-gall saper da, is a smaller species 
than S. tridentata (fig. 52) . from 10 to 12 mm. in length and uniformly 
hght gray in color. The antennae are annulate. The larva feeds in 
the branches of livi ing poplars and willows, causing a swelling or gall 
