of the 3'ear, and niaj' be seen crawling a])Out orcliard trees and beginning 

 to burrow through the bark. After penetrating to the sapwood, feeding 

 as she goes, the female constructs, partly within the l)ark and partly in 

 the wood next to it, a vertical gallery or brood chani1)er, and along the 

 sides of this at very short intervals gnaws little pockets in wliich she 

 deposits her eggs. The minute, whitish, grul)-like larva- hatching from 



these eggs excavate little side galleries, 



ISM^i j-l^^iJlli^ which start out at right angles to the brood 



'i^ ^ ■5-^^f,if/'l chamljer but soon diverge and widen with 



R '///A the increase in size of the growing larva. 



W') '^d^/ZM I. tot, 



W ' ''' '^'tsW'^i Mucli more frequently this insect lives in 



*> ) / '' 3W^flx\..ri such numl)ers, witli its galleries so closely 

 packed together under the bark of a tree, 

 that it is with difhculty that individual gal- 

 lei'ies can be distinguished. A specimen of 

 the insects' work on the wood shown at fig- 

 ure 3, illustrates the crossing and recrossing 

 of the galleries of different larva*. Com- 

 pletecl main galleries measure from one-half 

 to two inches in length, and the average 

 number of eggs dei)(»sited in each l)}^ a sin- 

 gle female is said to be al)0ut eight3^ 



The parent l)eetle, according to the studies 

 of Dr. J. B. Smith at New Biimswick, N. J., 

 occupies less tlian a week in the construc- 

 FiG. s.-Gaiieries of scoi.utus nnju- ^i,,,-, „f ^\^q brood chamber, the eggs hatch 



/o.sMS on twiR under l)ark: (/. », main n i i ^ • 



Kaiierics; z>, /-.side or larval Kaiior- withiii three days, and the larva is about 



ittaining maturity. The 

 shown in natural curved 

 position at figure !,</. is white in color, with a small yellowish head and 

 brown mandiJ)les, and its surface is much wrinkled. When aljout to 

 transform, tlie larva foi'ms at the large end of its gallery an oval cliam- 

 ber, usually in the wood, but sometimes partly in the bark, and here the 

 pupa.l stage is assumed. The period of the ])uiia, state as observed in 

 moderate weather, at Washington, I). V., is seven days; in cooler 

 weather of spring or autumn this mayl)e extended to ten days. Allow- 

 ing for both the shorter and longer periods in the development of the 

 preparaioiy stages, which must exist in the diilVi'enl temperatures of 

 midsummer, autumn, and spring, we have api)roximately a life cycle of 

 four to six or perhaps more weeks. 



- c 



ies : <-, <•, pupal rolls— natural size t^ycntv da\'S in 

 (after Rat/eburj;). 



full-grown larva. 



THE NU^inKli OP (iKNEKATIONS. 



The earlier wi'itcrs on the fruit-tree bark-beetle look little account of 

 its development, evidently being of the opinion that it i-ecpiired a year 

 to attain maturit.v. Thus, Sclimidbergei', wi'iting in ISoT states that in 



