216 



STATE BOARD OF AGRICULTURE. 



Fig. 14. Work of four-spotted Beaa-weevil, on cow-pea, slightly enlarged (Original). 



POWDER-POST BEETLES. 



(Lyctus spp.) 



Small beetles that tunnel in the sap-wood of timbers, either in the log, boarder in floors, 

 frames or linished furniture. 



The steadily increasing scarcity of good heart-wood for building pur- 

 poses, has led to occasional loss from powder-post injuries. Thus far 

 the reports of injury have been mostly confined to injury done to floor- 

 ing, probably for the reason that in flooring the work is more conspicuous 

 than in other parts of house construction. The agents that cause the 

 trouble are small beetles which tunnel through the sap-wood, excavating 

 it more or less completely and occasionally coming to the surface where 

 small heaps of fine, flour-like waste are thrust out. These little heaps 

 usually lead to the detection of the pests. Further investigation leads 

 to the discovery that the wood is pierced by small tunnels, sometimes 

 so profusely that little of the original stock remains except the outer 

 shell and some fibres, extending here and there, inside. The work of 

 these creatures is well known further South and is perpetrated by sev- 

 eral species. We have been unable to obtain perfect specimens of the 

 culprits in Michigan, owing to the fact that their depredations have 

 been in finished oak and maple wood-work, where it was not desirable 

 to cut out pieces for splitting, but fragments of the beetles which have 



