APPENDIX. 



841 



indication will be a withering of the leaves, while a closer examination will 

 show the bark to be more or less shriveled, as can be seen by referring to 

 the photograph in Fig. 1 ; and later, when the adult beetles emerge, the 

 small "shot holes '" will be conspicuous. If the bettles attack a large limb 

 or trunk, the work may go on for some time before it is observed ; but 

 usually one will detect the flow of sap, especially if it be a stone-fruit tree, 

 where the exudation of drops of gum will be sure to attract attention, and 

 may even be very conspicuous and run down the tree to the ground. 



HABITS AND LIFE-HISTORY. 



The fruit-tree bark-beetle is a small cylindrical beetle about one-tenth 

 of an inch in length and one-third as wide as it is long ; nearly or quite 

 black in color, with the very tips of the elytra or wing covers and portions 

 of the legs reddish brown. Under a hand lense one can make out the 

 peculiar markings on the back — thorax and elytra — and the short hairs 

 on the head and wing covers. A fair idea of the general appearance of 

 these beetles as seen under a lense can be had by observing the drawing of 

 one magnified in Fig. 2, a, while a side view in outline is shown in Fig. 2, b. 

 This beetle belongs to the family IScohjIuhf, which includes a number of 

 similar, small bark and wood-boring beetles that the ordinary observer will 

 not be able to separate from the one under discussion except by a close 

 observation of its habits and work. 



Fig. 2— The Friiit-Trce Bark-Beetle, Scol.tjtux riuiulnstm Katz. o, adult beetle; 

 b, same in profile; c, pupa; d, larva. All magnified about ten times. 

 (From Chittenden, circular 29, S.S. Div. Enfomology, U. S. Dept. of 

 Agriculture.) 



The adult beetles begin to emerge about the last of March in most sea- 

 sons, and may soon begin to feed by eating small round holes through the 

 bark of the tree. These holes are usually made near the base of the larger 

 limbs, and about forks and old scars or lateral spurs, but are also common 

 on the smaller limbs and even on the small twigs : while in badly infested 

 trees they may occur on the trunk as far down as to be within a short dis- 

 tance of the ground. The holes through the bark are small, not much 

 larger than the cross-section of a large pin. or about one-eighteenth of an 

 inch in diameter; and for this reason are frequently spoken of as "pin 

 holes," and the beetles as the "pin-hole beetles."' Where these holes are 

 very numerous they give the limb the appearance of having been shot or 

 peppered full of holes with fine bird shot : and this again has led to another 



