Larval Development of the Native Elm Bark Beetle, Hylurgopinus rufipes (Eich.), in Massachusetts*

As part of a study of the development of Hylurgopinus rufipes (Eich.) beneath the bark of elm, the following experiments were conducted. Logs of the American elm, Ulmus americana L., between 5 and 8 inches in diameter and about 4 feet long, which had been cut from one tree, were laid horizontally in a single row across two cither logs so they were raised slightly off the ground. The test logs were laid with the long axis in a northwest-southeast direction. They were under moderate shade in a wooded area. About once a week during the spring, summer and fall of 1936 when immature stages of only the first generation of the beetle were beneath the bark, a 4-inch cross section was cut from a log, and all the live stages of H. rufipes present were collected and preserved in 80 per cent alcohol. The bark on each cross section of log was cut into four quarters, which represented the top, bottom and two sides of the logs. One side faced the northeast, and the other the southwest.