THE DAVEY INSTITUTE OF TREE SURGERY 
146. The control is the same as for the other species, with the 
first consideration being given to keeping the trees in a healthy 
condition. 
> 20. MOTTLED WILLOW BORER 
Family CURCULIONID. Species Cryptorhynchus lapathi Linn. 
147. This is an introduced species, belonging to a family con- 
taining a number of notoriously i injurious species, but only a few 
borers. This species was first reported in this country in 1887, 
near New York, but has since spread throughout the Northeastern 
States and westward across the Mississippi. It is very destructive 
to nursery stock, working on willows, balm of Gilead, cottonwood, 
and several of the poplars. 
148. It can be controlled to some extent by spraying with 
strong arsenate of lead, to kill the beetles when feeding upon the 
bark. 
HYMENOPTERA 
149. This order contains comparatively few wood borers of 
importance. Among the eating insects it is more important. 
21. PIGEON TREMEX 
Family SIRICIDA. Species Tremex columbia Linn 
150. This is one of the larger of the Hymenoptera, and is 
preyed upon by one of the largest of the parasitic species of the 
same order. In the early literature it was known under the name 
Sirex columbia Linn. 
151. The adult is a saw fly with four clear wings, with a 
spread of about two and one-quarter inches. The black and yellow 
cylindrical body is provided at the end with a horn or ovipositor 
about three-eighths inch long. The female can frequently be 
seen in the latter part of the summer upon dead or injured maple, 
elm, oak, sycamore or other trees with its ovipositor, or “saw,” 
thrust into the wood. The infested trees are frequently full of 
round holes about the size of a lead pencil. In laying the eggs the 
female frequently gets the ovipositor so tightly wedged into the 
wood that she cannot get it out. Dead specimens can frequently 
be found in this position. 
152. On the same trees can frequently be seen a large, long- 
Pisce, dangerous looking four-winged fly, with a long ovipositor 
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