130 THE EEPOET OF THE No. 36 



Mr. Chrystal : Prof. Gillette states in his paper that on seeing the species of 

 cooleyi he described it as a new species and said that this species was confined to 

 the Eocky Mountain region. The state of the spruce in the Park was very bad ; on 

 careful examination about 60 per cent, were found to be beyond hope of control, 

 but the rest could be sprayed, even to a considerable height. 



Prof. Caesar: It is quite an interesting matter of observation at Guelph to 

 note that Chermes abietis and Chermes similis have, the last few years, been almost 

 totally controlled by some natural enemy. Since this western species is a native 

 insect one would expect that sooner or later we should have natural means of 

 control of it too. 



Me. Tothill: There has been an outbreak of presumably Chermes in New 

 Brunswick. This outbreak was exceedingly conspicuous about three years ago and 

 Professor Caesar will know fully well, the outbreak has been brought under com- 

 plete control. 



The President: If there is no further discussion on this paper we will pass 

 on to the next and last of this session. There are really two papers but they will 

 be taken as one and read consecutively. 



THE CABBAGE MAGGOT— AUTUMN DEVELOPMENT IN BEITISH 



COLUMBIA. 



(Phorhia hrassicce.) 



E. C. Treherne, Field Officer, Dominion Entomological Laboratory, 



Agassiz, B.C. 



The matter of autumn development in the life-history of the Cabbage Maggot 

 is obviously of great importance in the control of this fly. On the basis of the 

 knowledge obtainable in the autumn rests the question of autumn cultivation and 

 the destruction of the refuse and debris resultant from the summer's crop. Still 

 further great bearing will be obtained on the early spring development, inasmuch 

 as little change is undergone by the spring by these forms entering upon the winter. 



I do not propose, at this moment, to present all the information that has been 

 obtained during the past few years in British Columbia on the life history and 

 characteristics of this important pest, but merely to confine myself, in the time 

 allotted, to a consideration of the developments that occur in the autumn. 



Inasmuch as climate may offer changes and locality present differences, I shall 

 confine myself strictly to conditions that prevail at Agassiz, B.C. (Lat. 49.15, 

 Long. 121.40, 52 feet above sea level), which in themselves are comparable to the 

 entire Lower Eraser Valley or what is known as the " Lower Mainland " of the 

 Province. 



It is my belief that opinions generally consider that the Cabbage Maggot Fly 

 passes the dormant winter season mainly in the pupal state in the soil surrounding 

 cruciferous roots or imbedded in the root itself. There are also opinions ex- 

 pressed from various quarters that there is a "possibility" that the fly may pass 

 the winter in the adult condition. It is not my intention to enlarge on these 

 expressions, but inasmuch as it is our duty to take careful observations in each 

 locality where this fly is a pest and the growing of vegetable crops js a leading 

 industry, I merely wish to offer a contribution on the life characteristics of the fly 

 in the locality above mentioned. 



