77 



the attacks of other insects are permanently injured, but apparent!}' 

 normal trees are also attacked and sometimes completely' recover -with- 

 out assistance. Stone-fruit trees, especialh' peach, if in condition, 

 exude such quantities of gum that the beetles are repelled and abandon 

 their burrows witliout mining to any extent under the bark or deposit- 

 ing their eggs. As long as there is a vigorous flow of sap there is little 

 danger of serious injury, but after frequent attempts to obtain lodgment 

 the beetles may so "bleed" a tree that, in course of time, thej' are 

 able to attain their purpose, when the death of the tree is assured. 



Another form of injury is the destruction, at the beginning of spring, 

 of small twigs together with the leaves which they bear. The beetles 

 are also reported to destroy' leaves l)y boring into the base of the buds 

 at their axils. 



Injur}', then, is mainly due to beetles of the first generation working 

 upon the terminal twigs in spring and afterwards of later generations 

 on the trunks and larger limbs of trees. 



In common with most diurnal species this insect is found more 

 abundantly on the exposed sunny side of living trees, which being drier 

 would exude less sap, and for that reason be more available as food. 



DISTRIBUTION AND SPREAD OP THE SPECIES. 



From its first center of introduction in the United States, whether 

 central New York or elsewhere, this species had spread, presumably in 

 the main by the distribution of nursery stock, from infested to unin- 

 fested districts until, three years after its first observed occurrence in 

 bS!^|, it was reported as injurious in localities in New Jerse}^ Pennsyl- 

 vania, Missouri, Maryland, and the District of Columbia. In the suc- 

 ceeding five 3'ears it was reported successively from Massachusetts, Vir- 

 ginia, Georgia, and South Carolina, indicating a wide disti'ibution at 

 that time. In 1SS8 it was brought to the attention of Dr. S. A. Forbes 

 by its depredations in the State of Illinois, and as a consequence was 

 given special study in that State. ^ 



A perusal of the list of localities in which this species is known to 

 occur ill the United States shows that it is an inha])itant of the Upper 

 Austral lile zone, and tliat it is now resident in nearly every State of 

 the Carolinian division, as well as in a few that lie within the Transi- 

 tion. This includes territory from Massachusetts, New York, and Mich- 

 igan in the North to Alabama, and (ieorgia in the South, and Missouri 

 and Arkansas in the West, a total of nineteen States and one Territory 

 in which it has been reported to occur in injurious abundance in one 

 or more known localities. 



IJKK HISTORY. 



As early as the middle of Mai-ch, first of Api'il or later in May, accord- 

 ing to locality and season, the parent beetles make their first appearance 



1 Seventeenth Rept. State F>nt. Illinois for 1889 and 1890 (1891), pp. 1-20. 



