THE SPRUCE INVESTIGATION. 263 



what paler color, although the marking on the wing covers and 

 the size is the same in both species. It passes the winter in 

 all stages from larva to adult, in the bark in which it is bred, 

 the latter sometimes in the loose bark and moss at the base of 

 the tree. The adults appear in the spring, soon after the bark 

 beetles commence to emerge from their winter quarters and fly 

 to the trees, logs, or tops which are infested with bark beetles. 

 There they station themselves beneath loose flakes of bark, 

 awaiting an opportunity to pounce upon any bark beetle that 

 comes near. They also move rapidly about over the bark in search 

 of the prey, or the entrances to the bark beetle galleries in 

 which the females deposit their eggs. The eggs soon hatch into 

 minute active worms, which find their way into the egg and 

 brood galleries of the bark beetles, where they feast upon the 

 eggs and young found there until they have attained their full 

 growth, when they leave the inner bark and excavate cavities 

 in the outer corky bark in which they change to pupae and 

 adults. The larvae resemble that of the European Clerid, il- 

 lustrated on another page. Indeed, it is scarcely possible to 

 distinguish one from the other. 



This Clerid attacks and feeds upon all kinds of bark beetles 

 which infest the spruce and pine and has also been found 

 attacking bark beetles in deciduous trees. It is widely distrib- 

 uted over the State and doubtless has a wide range throughout 

 North America. It is a common insect wherever the pines and 

 spruces grow in the State, and doubtless exerts a considerable 

 influence in preventing the undue increase and devastations of 

 pine and spruce bark beetles. Unfortunately, it also has its 

 enemies to contend with, since it has at least two parasites, one 

 of which I have reared from the larva and the other from the 

 adult. The first, which is an internal Braconid parasite, appar- 

 ently attacks the full grown larva, when it enters the outer 

 bark to pupate. This parasite is in turn, apparently, attacked 

 by another parasite, which I have bred in large numbers from 

 the larvae of the Clerid, The parasite of the adult is a two- 

 winged fly, resembling a small house fly, which deposits an egg 



