INSECTS AFFECTING PARK AND WOODLAND TREES 63 



pointed at each end and rather less than V20 of an inch in lencrth. It is 

 very probable that tlie life cycle is completed within 12 months, though no 

 observations on this point have been recorded to our knowledi^e. 



Parasites. This large borer is a common prey of an exceedingly 

 interesting parasite known as the lunate long sting, Thalessa lunator 

 Fabr., which is a slender brown and yellow, wasplike insect about lyi inches 

 long and with a delicate tail or ovipositor about 3 inches long, whence its 

 common name of long sting. This beneficial parasite is very conspicuous 

 and may be frequently seen with its long ovipositor arched over the back 

 and the membrane of the terminal segments of its abdomen distended as 

 it forces its slender tool deep in the wood, in an effort to place its eggs in 

 the vicinity of a borer. The male is a much smaller insect than the female. 

 On splitting open a log containing numerous larvae, the white legless mag- 

 gots of this parasite may be found with mouth parts inserted and sucking 

 the life fluids of its hapless prey. These parasites emerge from the trunk 

 of the tree through holes of a slightly smaller size than a common lead 

 pencil. The various stages of this insect are well shown in figure 6. 



Food plants. This insect works more commonly in maples and elms in 

 New York, probably because there are more of these trees offering condi- 

 tions favorable for its development. It has also been recorded as attacking 

 apple, pear, beech, oak and sycamore. 



Distribution. This species has been recorded from Canada, and the 

 northern Middle States and Missouri by Norton. 



Remedial measures. This insect is so rarely injurious in the United 

 States that active remedial measures will hardly ever be needed. It should 

 suffice in most instances if the trees are kept in vigorous condition. It is 

 also advisable on the score of economy and beauty, if on no other account, 

 to cut and burn all trees badly infested by this insect. 



Bibliography 

 1862 Harris, T. W. Insects Injurious to Vegetation. Ed. 3, p. 536-38 

 1890 Packard, A. S. U. S. Ent. Com. 5th Rep't, p. 379-81 

 1898 Felt, E. P. Fish, Game and For. Com. N. Y. 4th Rep't, p. 389-90 



