388 HOUSEHOLD INSECTS 



in Michigan, but again only in sap wood. We have 

 found them injuring the timbers of barns. 



It seems strange that these insects can find nutriment 

 enough in the dry wood they chew to sustain life. It is 

 a fact though that they do thrive on their diet of dry 

 wood and the older and more seasoned the wood is the 

 better the insects seem to like it and the more they seem 

 to multiply and thrive. The conditions which seem most 

 favorable for the attacks of the powder-post beetles are 

 perfectly dry wood material or sap wood that has been 

 stored away for one or more years. Manufactured 

 articles, of considerable age, timbers and floors of old 

 houses offer favorable points of attack. As a rule, the 

 insects seem to prefer wooden articles that are not painted, 

 although they will attack old wood that has been varnished, 

 painted, or otherwise finished. 



The adults of the powder-post insects are, for the most 

 part, small, slender, dark brown to nearly black beetles. 

 Some of the common species are not over three-sixteenths 

 to a quarter of an inch in length. The species vary 

 greatly in their habits and life history. When the wood 

 attacked lies out-of-doors exposed to normal climatic 

 conditions, the winter is passed by the insects in their 

 burrows in an inactive dormant condition. When the 

 beetles are working in wood in heated rooms, their activity 

 may continue throughout the year. Normally, activities 

 begin in the spring and the eggs are soon laid by the parent 

 beetle. Each female deposits many eggs and as several 

 females may lay their eggs in the same piece of wood 

 there may be scores of larvae within a comparatively 

 small space. As a result, the whole interior of the in- 

 fested material may soon be reduced to a mass of dry 



