3^^ 



XEV. YORK STATE MUSEUM 



this species has been estimated by various correspondents at lo, 50 and 



even as much as gc^. 



Description. Tlie parent beetle is a small, rather thick, light or dark 



brown insect about ? 16 inch in length. It presents no distinctive character 

 which will enable its separation from allies, and it is 

 more easily identified by its work, as no other 

 insect of its size causes so much injur\" io spruce. 

 XJt^'T^fs^ The middle tibia is illustrated at figure 85/;. 



L^//''/ /Tp Its attack is limited, as observed by Professor 



Peck, mostly to the larger trees, it rarely being 

 found in those less than 10 inches in diameter. 

 The most characteristic feature of injury is the 

 browned tops, and an examination of the trunk usu- 

 ally results in finding tubes of pitch, which are 

 pushed out from the wounds made by the beetles 

 when excavating an entrance. The adult galleries 

 are about ^g inch in diameter and run lonoitudi- 



Dendroctonu spice .1- ' 



perda (original) ually for a dlstauce of several inches, eggs being 



laid on either side and the larvae working more or less obliquely and very 



irregularlv from this central gallery [pi. 61, fig. 1]. Their burrows are 



easily recognized by their irregular, more or less tortuous course and 



expanding character. Adult galleries preserved by infiltrated pitch are 



shown at plate 61, figure 2. These illustrations are specially valuable as 



they represent material taken by Professor Peck some 30 years ago. 



The following more detailed account of this insect's work by Professor 



Peck, will also proxe of service. 



For the purpose of gaining more knowledge of the insect, I cut down 

 at South Pond, a tree that had recently been attacked by it. It was about 

 20 inches in ciiameter at the base ; the foliage was still fresh and green, and 

 there was nothing, except the perforations in the bark, to indicate that it 

 was at all affected. The bark peeled from the trunk without much dififi- 

 culty, the sapwood was perfectly sound, and the heartwood also, except a 

 small portion in which there was a slight appearance of incipient decay. 

 Longitudinal furrows, varying from one to six inches in length, were found 



Fig. S5 .Middle tibia< 

 graphus rufipe 



