TOMICUS TYPOGRAPHIC. 



239 



impressed striae, somewhat finer posteriorly, the intervals flat, 

 not punctured except at the sides and apex ; apical excavation 

 dull and irregularly punctate, with four teeth on either side, of 

 which the third is the largest. 



1}. Life-history. 



Flight-time at the end .of April or in May, at higher altitudes 

 at the beginning of June. Under favourable circumstances a 

 second brood may appear in July or August. The beetles are 

 found in pairs boring into the trunks of large spruce trees 

 under the crown, especially on 

 the sunny side ; when they 

 reach the bast, they prepare a 

 breeding chamber ; after pairing 

 the ? excavates one or more 

 galleries running in the long 

 axis of the trunk, which besides 

 the original bore-hole, may con- 

 tain 2 to 5 air-holes. On the 

 right and left of the mother- 

 gallery she bites out little re- 

 cesses of the size of a poppy-seed, 

 and lays in each an egg, generally 

 to the number of 30 to 50, but 

 sometimes as many as 120, 

 which she covers with fine 

 wood-dust. 



After 14 days the first larvae 

 appear in May and June, before the egg-laying is quite 

 completed, and eat out slightly winding galleries in the bast, 

 somewhat at right angles to the direction of the mother 

 gallery, pupating at their ends in a chamber in the bast. 



The newly disclosed beetles leave the trees through round 

 holes in the bark in July or the beginning of August, and 

 hibernate in stumps, cracks in bark, under bark, and more 

 rarely in moss. When they come out early, before the end of 

 June and under other favourable circumstances, they at once 

 commence to lay eggs for a new brood, from which beetles 

 may appear during September at the latest. 



Fig. 100. Burrows of T. typographies, 

 L., in spruce-bark. (Natural size.) 



Commencement of mother-galleries 

 with pairing-chamber (a) and egg- 

 (b). 



