THE GENUS DENDROCTONUS. 



159 



emerge. They then bore a few exit holes or utilize the ventilating 

 holes in the old gallery, through each of which many individuals 

 emerge. In localities where this barkbeetle is abundant it sometimes 

 congregates in swarms of greater or less extent, accompanied by asso- 

 ciates, guests, and enemies. 



The flight habits of all of the species of Dendroctonus are more or 

 less obscure, but some observations have been made on the swarm- 

 ing habits of this species, as recorded by the writer in Bulletin No. 56 

 of the West Virginia Agricultural Experiment Station, pages 346-348, 

 which are perhaps worthy of repetition in this connection : 



Fig. 101.— Western yellow pine showing work of the red turpentine beetle, Flagstaff, Ariz. (Original. ) 



Returning to Morgantown, W. Va., on May 12, I learned from my assistant, Mr. 

 W. E. Rumsey, and others, that a great swarm of barkbeetles had passed through 

 Morgantown on May 4. They were especially abundant in and around furniture 

 factories and new houses that were being painted, and wherever there was an odor 

 of turpentine. In fact, they came, as it was expressed, "like a hailstorm," into 

 open windows and doors, and were the cause of considerable alarm on the part of the 

 inhabitants, who thought that a plague of bugs had visited the place. The new 

 greenhouses that were being constructed and painted at the experiment station were 

 central points of attraction. Here they occurred like swarms of bees. 



While this remarkable swarm consisted mainly of the turpentine barkbeetles, it 

 would appear from the dead and living examples that I found in the greenhouses 

 and adhering to the paint that it was accompanied by numerous species of bark and 

 timber beetles and also by some of their enemies. I was greatly disappointed that 



