411 



biological method should be the principal means of primary defence 

 in desert or semi-desert portions of the colony, or in parts where native 

 labour is scarce and crops are not immediately menaced. Under other 

 conditions it should be used as an accessory to other control measures. 

 The following were the preferred food-plants of Schistocerca peregrina : 

 Peganum harmala, Salsola vermiculata, Anabasis articulata, Noaea 

 spinosissima, Artemisia herba-alba, Atriplex halimus and a species of 

 Tamarix growing on the banks of rivers. 



BoRODAiEvsKY (P.). HafinwAeHifl bi> 1913 rofly Hafl-b yKMSHbio speA- 

 Hbix-b HactKOMbixij MoxotAOBCKOM A^'f^ MoxoiAOBCKaro ntcHH- 

 HeCTSa Mmhckom ry6epHil1. [Observations on the hfe of insect- 

 pests in the Mokhoiedov woods of the Mokhoiedov Forestry of 

 the govt, of Minsk in 1913.]— « JltCHOR }KypHaJI'b.» [Forestry 

 Journal], Petrograd, xlv, no. 8-9, 1915, pp. 1222-1247, 12 figs. 



The first instalment of this paper describes a number of experiments 

 with bark beetles. Some pine trees were felled and cut into logs on the 

 10th March; ten of these logs, from 9-16 inches thick and 6|-13 feet 

 long, were sunk vertically into the soil in the wood, while seven others, 

 13-15 inches thick and 4-6 feet long, were put vertically on stands 

 12-19 inches above the ground ; others were placed horizontally on 

 trestles at heights of 4-14 inches and two, 16 and 20 feet long 

 respectively, at a height of 3| feet. The cut surfaces of the logs 

 were coated with paraffin. These logs were kept under observation, 

 and as they became infested, the mines were numbered and 

 periodically opened. 



Myelophilus minor, Hart., was on the wing in the second half of 

 March and, owing to a spell of cold weather, again at the beginning of 

 April. On the 31st March o\Tiposition had already taken place and 

 mines from 1^ to 22 mm. long were found in some trees in the woods, 

 while on the trap logs the boring was just beginning. Of these, two 

 placed horizontally 3| feet above the ground showed the greatest 

 infestation, while on those at 8| and 10| inches, few or no beetles were 

 found. The beetles did not ^settle on the logs placed vertically. 

 Oviposition extended over nearly two months, from the 28th 

 March. A table showing the results of opening the tunnels in the 

 horizontal logs in March, April, May and June is given, with their 

 respective measurements at those dates. The first larvae were dis- 

 covered on 21-23 April, i.e. 17-19 days after the beginning of 

 oviposition ; thev began to bore into the wood on the 2nd May. 

 On the 22nd May the larvae of M. minor were observed to be attacked 

 by larvae of Cerambycids and some other insects, including another 

 Scolytid, Crypturgus cinereus, and to a very small degree by C. pusillus. 

 The borings of C. cinereus were observed on 2nd May. The larvae of 

 C. cinereus feed in and on the bark, and pupate in the bark. The next 

 generation of adults of C. cinereus was found on 25th July, their hfe- 

 cycle having lasted about 81 days. It is thought that the destruction of 

 M. minor by C. cinereus is effected mechanically by crushing the 

 eggs and larvae when the tunnels of the former cross those of the 

 latter. The cycle of development of M. minor is divided into 

 eight stages : (1) egg, (2) larva underneath the bark, (3) larva in the 



(c;ui) ki 



