G BULLETIN" 886, IT. S. DEPARTMENT OF AGRICULTURE. 



packed for an inch or two with excelsior-like strings of wood (PL IV, 

 B) 3 evidently as a safeguard against the accumulation of too much 

 moisture while the insect is undergoing its transformation to the 

 adult stage. 



Probably the behavior and the metamorphic development of this 

 species are affected to a considerable extent by differences in latitude. 

 No doubt the borer feeds more extensively and grows more rapidly 

 the first season in the South than in the North. In West Virginia, 

 of 16 individuals in which the duration of the larval period was ob- 

 served, 1 lived in the tree 2 years, 14 lived 3 years, and 1 lived 4 years. 



THE PUPA. 



The pupa (PI. I, C, E, F; PI. IV, B) is characteristic of the family, 

 being creamy white in color with the rudimentary legs, wing pads, 

 and antennae folded close to the body. In form it is slender, averag- 

 ing 1 7 mm. in length by 5 mm. in width. The dimensions of the cell 

 which it occupies (PI. I, E, F; PL IV, B) are only slightly greater 

 than those of the pupa itself. The average size of this cell is about 

 20 by 8 mm. The restricted quarters of the pupa limit its move- 

 ments much more than is the case with the pupa of the common 

 borer, Saperda Candida, whose pupal cell may be 2 inches or more 

 in length. In West Virginia pupation takes place in April, one speci- 

 men being found in the pupa stage on April 3. The pupal period 

 lasts from four to six weeks. This stage, also, of the insect's develop- 

 ment is probably affected in time limits by differences in climatic 

 conditions due to latitude. 



THE ADULT. 



The adult of this borer (PL II, A-D) is a handsome beetle, the 

 females of which are from 15 to 20 mm. and the males from 12 to 

 16 mm. in length, the females being much more robust than the males. 

 The upper parts are cinnamon brown with a broad white stripe on 

 each side of the thorax, a large, oblong, white spot, notched at the 

 ends, on the middle of each elytron, and a smaller, comma-shaped, 

 white spot midway between each of these and the apex. There are 

 usually a minute white spot on the thorax just in front of the scutel- 

 lum and one each on the humeral angles. The sides are white and 

 the underparts of the abdomen and thorax, and the head, antennae, 

 and legs are brown. 



After transforming, the beetles remain in their pupal quarters for 

 several days to harden and then escape by gnawing a circular hole 

 through the bark barrier that has shut them in. (PL V, A, C.) The 

 exit hole in the bark is from 5 to 6 mm. in diameter, that of the male 

 being smaller than that of the female. 



On escaping, the beetles seek seclusion among the branches where 

 they rest in comparative inactivity during the brighter part of the 



