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, pa^es 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. A'a., 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 
