FAMILY SCOLYTIDAE 



571 



The above describes the Hfe history of one generation or Hfe-cycle of the 

 insect, but does not account for the life of the species throughout the year. 

 It has been found that it passes through several generations in a year, 

 the actual number depending upon the climatic conditions of the early 

 and late parts of the season. 



My observations, carried over a series of ten consecutive years, tend to indicate that in 

 ordinary years the insect passes through three to four generations (the last a partial one) 

 in the course of a year, as follows :— 



Generation I. 



4th week in April 



1st week in May to ist week in June . 

 1st week in June to end of June . 

 3rd week in Jure to ist week in July . 



Generation II. 

 4th week in June ...... 



1st week in July to ist week in August 



ist week in August to 3rd week in August . 



2nd week in August to 4th week in August 



Generation III. 



3rd week in August 



4th week in August to 4th week in September 

 4th week in September to 3rd week in October 

 2nd week in October to 4th week in October 



Kggs 

 Lai"vae 

 Pupae 

 Beetles 



Eggs 

 Larvae 

 Pupae 

 Beetles 



Larvae 



Pupae 



Beetles 



Generation IV (a partial generation). 



3id week in October 



4th week in October to 2nd to 3rd week in April of the 

 following year ......... 



(Most of these larvae will be overwintering larvae.) 

 If beetles of this generation mature it will probably be from eggs laid in the ist or 

 2nd week of October, when the generation would be as follows :— 



1st week in October 



2nd week in October to 2nd week in November. 

 2nd week in November to 4th week in November 

 3rd week in Novemljer to 3rd week in April of the follow- 

 ing year 



Larvae 



Eggs 



Larvae 



Pupae 



Beetles 



(These beetles will hibernate in the thick outer bark of old standing trees. 



5. 



major is a most dangerous pest to the deodar, and is, as far as is at 

 present known, one of the worst insect foes the tree has 

 Damagejomm^tted in ^o contend with. Trees of all sizes are attacked by the 

 beetle, from the largest tree in the forest to the smallest 

 sapling. It usually confines its attacks to sickly trees and trees broken by 

 snow or from other causes, in all of which the vitality has become lessened 

 and the upward flow of sap consequently decreased ; it also invariably lays 

 its eggs in newly felled unbarked trees when such are available. In forests 

 where such trees are not available or where circumstances have favoured the 



