THK WKSrKKN I'l X K-OKSTK) )Y I N<} T.A UK HKKTI.E. 2M 



ill the living inner l):irk. two iidults to n ^'iillcr\ . lOtru's occurnMl 

 sin<j;ly in niches on the sides. 



He estimated that as a fesuh of tii(> work hy this insect near Smiths 

 Ferry 30 |)er cent ol" standin;^ tindx'i- was dead and 5 per cent ^\■as 

 dyino;. This was at tlie worst |)oint of inl'estution, but scattered dyinj; 

 tiniher was foiiiid all over Boise and Payette hasins. The same con- 

 dition (>xtended into the liitter Ivoot Forest Reserve. 



OBSERVATIONS BY THE WRITER, 1905. 



The invest i»!;at ions l)y the writer durin<; the summer of 1905, so far 

 as they relatc'd to this sj)eci(>s, were mainly for the |>ur|)ose of deter- 

 miiiiiii,^ the |)rinci|)al facts in its life history and habits in the vicinity 

 of CeiitervilK^ and Smiths Ferry, Idaho. The results may he sum- 

 marized as follows: 



LIFK HISTORY AND II.VIUTS OF THE INSECT. 



HIBERNATION. 



While it is ))rol)al)le, as oh.served hy IIoi)kins at (Jrants Pass, 

 Orej]jon, that a few parent adults which enter the bark in the fall may 

 pass the winter in that stage, it appears that it is in the young to 

 matured larval stages that the insect normally passes the winter, each 

 individual in a separate mine or cell in the outer corky bark of the 

 tree in which it develo|)ed the previous summer and fall. The ear- 

 liest ol)servations at Centerville were made on May IS, when larva% 

 pupa^, and young adults were found. Some of the larva^ were small, 

 but the majority of them were mature and ready to change to pupa\ 

 The pupa> and adults had evidently transformed from larva^ since the 

 beginning of activity in the sjiring. 



The latest date on which larva? of the hibernating broods were 

 found was June IM. l'upa> were found as late as Jul}' 3, and adults 

 July 7. It is therefore evident that the majority of the over-wintering 

 broods develop to the adult stage by about the middle of June, but 

 broods from eggs deposited late in the fall may not develoj) until 

 nearly the middle of August. Adults begin to emerge in the latter 

 part of May and continue to do so through June and July and into 

 August. Thu^; the period of activity of the hibernating broods at 

 Centerville is probably from the first warm days in April and May 

 until about the last of July — apj^roximately *.H) days — the majority, 

 however, coming out in June and in early July. 



KIKST (iKNKKATlON. 



The first generation at Centerville begins with the first eggs depos- 

 ited, apparently about the last (»f June. i)y the adults devcdojied from 

 hibernating larva- and i)U|)a'. These eggs hatch in about 4 days after 

 deposition. The principal egg-laying period for this general ii)n is 

 evidently between the latter part of June and the first part of .Vugust. 



