47 



extensively upon the larvae of this birch-tree insect. This bird selects 

 a place on the trunk of the tree in which the larvse are concealed and 

 makes an incision in the bark which resembles that made by a pen- 

 knife if stuck into the bark in the same manner. This it does until it 

 locates the borer, when it proceeds to pick open the bark and remove 

 the insect. 



As in the case of injury ascribed to the two-lined chestnut borer, 

 there is still a certain degree of doubt as to whether or not this birch 

 borer is really the primary cause of the death of the trees. Our corre- 

 spondent is of the opinion that injury in Buffalo is due primarily to the 

 attack of this borer, since it has been observed attacking vigorous trees. 



That carelessness is one of the principal causes that has led to its 

 undue multiplication is evidenced by information furnished by Mr. 

 Adams. He states that the upper part of the tree in which it was first 

 noticed at work had been removed, but that about six feet of the trunk 

 was permitted to remain for use as a support for flower vases or for 

 some similar purpose. A surface as large as this would furnish oppor- 

 tunity for the development of perhaps many hundreds of this insect. 

 The material from which the identification of the species was made was 

 obtained by searching among wood piles which had been permitted to 

 accumulate. 



It is not improbable that woodpeckers and other birds would keep 

 this borer in check if unmolested by sparrows, and this invasion may 

 be accounted for, in a measure at least, by the absence of the insect's 

 natural enemies. 



A very singular thing in connection with the occurrence of this borer 

 in birch is that in spite of frequent search, extending over a period of 

 two years, our correspondent has been unable to find this insect attack- 

 ing any other tree than birch — a remarkable condition of affairs when 

 we consider the numerous observations by careful observers of its occur- 

 rence on poplar and willow. 



DESCRIPTION AND DISTRIBUTION. 



Agrilus anxius is shown in the accompanying illustration (fig. 17, a). 

 It is a rather large species of its genus, measuring between three-tenths 

 and nearly half an inch in length (7.5-11.5 mm.). It is of moderately 

 robust form, subopaque, olivaceous bronze in color. The last ventral 

 segment is oval at the apex; the punctuation of the prothorax is trans- 

 versely strigoso-punctate and its posterior angles are carinate in both 

 sexes ) the first ventral segment in the male is broadly grooved ; the 

 second more deeply, the groove being narrow and smooth (see b). The 

 serration of the antennal joints begins with the fourth joint. The elytra 

 bear each a rather vague longitudinal costa and the scutellum is trans- 

 versely carinate. 



As no common name seems to have been applied to this insect, it may 

 be called the bronze birch borer. 



