438 



Mayetiola destructor. There are two main broods in a year, one in 

 the spring and the other in autumn. Under exceptionally moist 

 weather conditions a supplementary spring brood may follow the 

 main brood, a summer emergence may occur on self-sown wheat, 

 and a second autumn brood may follow the first one. The controls 

 advised are proper preparation of the seed-bed, including the liberal 

 use of good fertiliser, and correct time of seeding, which can be 

 calculated for any point in the State. A table is given for determining 

 the date of safe sowing at various altitudes and in various latitudes. 



Beeson (C. F. C). The Life-History of Dmjows /wrim/s, Sampson. — 

 Indian Forest Records, Calcutta, vi, no. 1, 1917, 29 pp., 2 plates. 

 [Eeceived 25th July 1917.] 



Diapus furtivus, Sampson, is apparently distributed uniformly 

 throughout the sal forests of the Sub-Himalayan tract and of Central 

 India. Investigations carried out during the years 1913-1915 indicate 

 that the insect is not primarily responsible for the dying off of Shorea 

 robusta (sal), but is one of a number of shot-hole borers which attack 

 trees that already have diseased roots. Its attacks on healthy trees 

 are practically without any effect, and are not fatal to trees weakened 

 by defoliation, creepers, local conditions, etc. The insect breeds 

 chiefly in newly dead or felled trees and is active throughout the year. 

 The length of the life-cycle is usually about 10 weeks, but owing to 

 the prolonged egg-laying j)eriod, emergence is extended over a period 

 of five or six weeks. It is impossible to determine the minimum 

 number of generations in the field ; all stages of the insect are found 

 throughout the year and there are no marked swarm periods. The 

 borers construct a system of galleries in the sap-wood and heart- wood 

 of sal, the larvae feeding on an ambrosia fungus which grows on the 

 walls of the brood galleries. The wood-dust produced by the boring 

 is ejected by the male beetle from the tunnel entrance. 



Several species of Cucujids, Colydiids, etc., are predaceous upon 

 shot-hole borers of sal, but to what extent they attack D. furtivus has 

 not yet been discovered. Many of the predaceous species cannot 

 enter the galleries of the borer, owing to their size. The Clerid, 

 Tillicera assamensis, Stebb., is said to prey upon D. furtivus in Assam, 

 and two species of Stigmatium, at present unidentified, attack the 

 borers when swarming. The Curculionids, Phaenomerus smiderivalU, 

 Boh., and an imknown species of the same genus have been found 

 several times in galleries of D. furtivus, apparently feeding on dead 

 borers ; and a species of Chalcid, at present unidentified, has been 

 bred from D. furtivus broods. The red tree-ant, OecophyUa snwragdina, 

 F., is an important enemy of the beetle, a sal tree around which beetles 

 are swarming being usually occupied by an army of these ants. 

 Parasitic Nematode worms have been found in the bodies of several 

 beetles. 



The damage effected by the beetles takes the form of shot-holes 

 and fines and stained wood defects, the sale price of infested timber 

 being materially affected. The remedies suggested are early barking 

 on felhng areas and the removal of newly-dead trees in other parts 

 of the forestr 



