671 



20 per cent, of its larvae are killed before reaching maturity by a 

 Tachinid, but only those larvae which are under imperfect pitch tubes 

 are parasitised, so that the economic value of this parasite is practically 

 nil. On account of the long life-cycle of this pest, its elimination will 

 follow in any country where forests are properly cared for. The 

 isolation of areas susceptible to infestation should be the main control 

 measure. A watershed, one side of which is always subject to a 

 greater degree of sunlight than is favourable to this insect, or a suffi- 

 ciently wide belt of trees other than Douglas fir on the opposite side 

 of a stream, may entail the separation of such an area from neighbouring 

 ones. Small tracts which can be given attention for a few days 

 annually, may be kept comparatively free, and even if infested, the 

 removal of the larvae during the first year will prevent the development 

 of serious wounds. Destruction of the larva is the only remedy that 

 can be used to reduce an infestation. When the infested pitch tube 

 is found, it should be separated from the tree, and the exposed larva 

 killed ; to insure cleaner healing, the ragged edges of the wound 

 should be smoothed and painted with creosote. Freshly vacated 

 wounds may be treated in the same way. One experienced man can 

 clean and keep clean an area 50 miles square (roughly, 1,600,000 acres) 

 in the course of a few years. A bibliography of five works concludes, 

 this paper. 



Brooks (F. E.). The Parandra Borer 'as an Orchard Enemy.- U.S. 

 Deft. Agric. Washington, B.C., Bull. no. 262, 19th July 1915, 

 7 pp., 4 plates. 



Paravidra hrunnea, F., which has been popularly called the ash 



root-borer, chestnut telephone-pole borer and heartwood borer, is a 



very general feeder, attacking the live and dead heartwood and 



sapwood of a great variety of trees, including pine, black walnut, 



hickory, willow, beech, chestnut, chinquapin, oak, elm, tiihp, apple, 



pear, plum, wild and cultivated cherry, locust, Ailantkus, soft maple, 



basswood and black ash. It occurs over the greater part of temperate 



North America. P. hrunnea is a borer from which trees are in very 



little danger of injury so long as they are in vigorous condition. It 



enters the wood from dead or decaying places on the surface and is 



probably never found in trees whose trunks and larger branches are 



entirely covered with healthy bark. Any primary injury, including 



those by Chrysohothris femorata, F. (flatheaded borers), and Saperda 



Candida, F. (roundheaded borers), may result in attacks by P. hrunnea, 



which inserts its eggs into the surface wood of the dead spots 



whence the larvae extend their burrows. i\Iining proceeds for a period 



of probably three years, the galleries being extended upward more 



frequently than downward. Pupation takes places within the wood, 



the beetles working their way out through the larval galleries. They 



frequently return to the dead wood, and hide in the old galleries. 



Eggs are now inserted into the wood which forms the walls of the old 



burrows, and the borers of the new brood penetrate still farther into 



the A\ood. The work of P. hrunnea may be distinguished from tiiat of 



S. Candida by the fact that the former enters at a dead spot and throws 



no castings to the surface, whereas the latter enters hving wood and 



freely extrudes reddish yellow castings, which form small heaps at the 



