276 INSECT PEEVENTION. [Feb., 



being crowded. I confess that here, if the growth of the trees were 

 more equally straight (and this might, I should think, be obtained 

 by careful selection of the seed-bearers), we could desire nothing 

 better — as far as vigour and rapidity of growth are concerned — than 

 the German variety. I have some young trees, twelve years old now, 

 that are growing about three feet every year, and in very poor soil. 

 Although I have not visited the forests of Germany, I should think 

 the Germans, who are confessedly by far the best foresters in the 

 world, would not continue to cultivate their variety if it were destitute 

 of merit. David Cannon. 



INSECT PBEVENTION.* 



I. 



8N" the office which I have the honour of holding as your Special 

 Lecturer on Economic Entomology, I have felt that as I have 

 only occasionally the pleasure of addressing you it was, perhaps, 

 best at first to take some such special attacks as those of wireworm, 

 or turnip-fly, or such detached facts relative to the habits of injurious 

 insects as might be of service even considered separately. But in 

 matters of insect prevention, although it is very useful to know 

 precisely wliat methods are thought the best for preventing or 

 remedying each special kind of attack, it is a great deal more so to have 

 in our minds a principle or rule which will apply equally to a great 

 many kinds, and thus enable us to help ourselves as occasion may 

 require ; and to-day I wish to offer some observations on one of the 

 most important principles of prevention — that of the removal of 

 winter shelters. In other countries insects often sweep on in liordes, 

 devastating all before them, but here in these islands (excepting from 

 tlieir neighbourly visits) our insect troubles arise in great part from 

 the last brood of the pi-evious summer's pests, whicli will in many 

 cases have sought a winter shelter, or have been placed in it in tlie 

 egg form, at or near the root of their food plant. We need not sa}- 

 anything again al)Out the extent to which turnip-fly shelters during 

 winter, but so also does its near ally, the mustard-beetle, and 

 although we liave at present only a few observations on the Sitona, 

 or pea and clover weevil, these ])oint to stubble as being one of the 

 autumn shelters from which they start attack on the next spring's 

 clover. The autumn daddy-longlegs provide us, in pasture land 

 and clover leys, with the leather-jacket grubs, which people the 

 brok'en-up groimd with the devourers of the next crop, and it is not 



* A lecture delivered at the Koyal Ai,a-icultural College, Cirencester, by Eleanor 

 A. Orraorod, Consulting l^intomologist to the Royal Agrimiltural Society, and Special 

 Jji'cturer oa. Economic P^ntomology at tUe Royal Agricultural College. " 



