352 



REPORT OF STATE BOARD OF HORTICULTURE. 



THE FLAT-HEABEl) APPLE-TREE BORER. 



( Chrysobothris femorata Fab.). 

 GENERAL APPEARANCE AND NATURE OF INJURY. 



A much less dangerous, though more abundant, insect than any of the 

 preceding, is the flat-headed apple-tree borer. It belongs to a different 

 family of Coleoptera, the short-horned wood-borers or metalic beetles of the 

 family Buprestida?, and dilTers remarkably from the preceding in all its 

 stages as well as in its habits and life-history. 



The adult insect ( represented at h, Fig. 3 ) measures from a little less to 

 a little more than a half inch in length. It is flattened above, resembling 

 somewhat a snapping beetle, but it is not provided with jumping organs like 

 the Elateridte. The antennje are 

 short and serrate, the eyes large and 

 conspicuous, and the forelegs are 

 armed in front with a conspicuous 

 tooth. The upper sui'face of the 

 body is dark metallic brown, and 

 fresh specimens are coated here and 

 there with a powdery gray substance, 

 which is easily rubbed off. The 

 wing-covers are ornamented as 

 shown in the illustration, and under- 

 neath, as may be seen vv'hen the 

 insect is in flight, the body is a 

 bright metallic greenish blue. The 

 under surface is coppery bronze. 



Fig. 3 — Chrysobothrin femorata : a, larva; br 

 beetle ; c, head of "male ; d, pupa— twice 

 natural size ( original.) 



The males are smaller and may 

 further be distinguished from the females by their green heads as well ay 

 by other characters ( see Fig. 3, c. ) 



Unlike the round-headed borer the present species is diui^nal in habit, 

 being most active in the heat of the day and commonly found on prostrate- 

 trees and logs, or on injured trunks basking in the sunlight. The beetles 

 are active creatures, running ra^iidly and flying readily. 



This species attacks by preference diseased or dying trees, inhabits all 

 parts of a tree from the base of the trunk to the limbs, and is not restricted 

 in its ravages to fruit trees, but attacks also a variety of deciduous trees. 



In all these respects it differs from the round-headed borer, but agrees 

 with the latter in that it is injurious chiefly to young trees, its injuries being 

 practically confined to newly transplanted nursery stock and to trees which 

 have been weakened through any cause, such as careless pruning, or insuffi- 

 cient nourishment due to poor soil or drouth. There is a difference of 

 opinion as to the nature of damage, some writers taking the stand that 

 healthy trees are not injured at all. It is a well-known fact that many forms 

 of boring insects prefer injured plants, but when this is wanting do not 

 hesitate to attack perfectly sound growth, and records show conclusively 

 that the present species is included in this category. The general opinion 

 is that trees suffering from "sun scald " are most subject to attack, and the 



