729 



soil and the level of the larvae in it. In 29i holes in the soil among 

 pines mixed with birch and aspen, when at a depth of 4 inches, there 

 was an average temperature of 60-4° F. ; 100 per cent, of the larvae 

 were situated at that depth ; in soils with an average temperature of 

 59-8° F. at 4 inches, the proportion of larvae at that depth was from 

 80 to 99 per cent. ; with an average temperature of 59° F. from 

 70 to 79 per cent, and 57-2° F. from 50 to 69 per cent. When the 

 heat is considerable, the larvae do not remain near the surface of the 

 soil. When 100 healthy larvae of the second and third stages were 

 exposed to the sun for 20 minutes, 50 per cent, of them were killed. 

 Further experiments are necessary to decide whether ploughing during 

 spring and early summer, when the larvae concentrate near the surface, 

 is a directly destructive remedy or only acts indirectly by generally 

 improving the state of the plantations. Results in previous years 

 have shown that the larvae prefer a fertile black soil to a sandy one. 

 This led to experiments on the control of the larvae in sandy soil 

 by means of trap-holes filled with black soil. Two pairs of holes of 

 dimensions of 1 cubic metre were prepared in a pine forest on sandy 

 soil, at the end of August 1914, one of them being filled with black 

 soil, the other, the control, with sand ; both black soil and sand had 

 been previously cleaned and all animal and vegetable matter removed. 

 After 4 weeks, 39 larvae were found in the holes containing black soil, 

 and only 6 in the sand. 



The total cost of this proceeding, even if done at the most favourable 

 time, in spring and early summer, is however not much less than that 

 of renewing the plantations. 



Beeson (C. F. C), Ips hngifoli't. Steb., as a Pest of Chir Regeneration 

 Areas. — Indian Forester, Alhhabad, xli, no. 9, September 1915, 

 pp. 317-325. 

 Ips {Tomicus) longifolia was first recognised as a pest of Pinus 

 longifolia (chir pine) in 1911, when it was shown to attack the mature 

 trees. Later observations in 1913-1915 have shown that seedlings and 

 saplings are not immune and this beetle is able to breed in trees of all 

 ages, young pines being rapidly killed. Recent attacks suggest that 

 the development of the bark-dwelling habit of the beetle is associated 

 with the introduction of artificial conditions into the forest and 

 particularly those which result from heavy fellings in the neighbourhood 

 of advance growth. /. longifolia was occasionally accompanied by 

 Poh/graphus longifolia, Steb., Platypus hiformis. Chap., and Cryphalus 

 major, Steb., but in all instances these were secondary infestations. 

 In all cases perfectly healthy trees were attacked and killed in from 

 4 to G weeks. Attack by one generation was sufficient to cause the 

 death of the majority of the trees. The primary centres of infestation 

 were situated in or near a felling-area and attacks began in the May 

 or June following felling operations. Most severe injury occurred when 

 felling was delayed or protracted into the hot weather, or where 

 considerable quantities of refuse were left on the felling-area after 

 removal of the timber. From these facts, it is clear that the swarms 

 of beetles which attacked the young growth developed in the refuse 

 and logs of the felling-area. The winter broods of /. longifolia develop 

 in trees felled in October and November, wliich are allowed to remain 



