PREVENTION AND DESTRUCTION OF INSECT PESTS. 491 



imago and larval stages, the adults devouring leafage and the larva3 

 rootage of plants. Weevils are always extremely sensitive, and fall 

 to the ground at the least shock, when they curl their legs in and 

 feign death. The larvaj are always curved, white, wrinkled, foot- 

 less grubs, and generally feed close to the surface during the 

 winter months. Many weevils {Otwrhynclms) have no wings. 

 This genus contains such noxious species as the raspberry weevils 

 (0. picipes and 0. sulcatus) and the plum weevils (0. fitsdpes and 0. 

 tenehricosus). They all hide away during daylight, coming out at 

 night to feed. We can best catch these depredators by "jarring" 

 the trees over tarred sacks or boards at nights, when the weevils 

 fall off and arc caught in the tar beneath. Jarring may generally 

 be employed for this group of beetles. Some other weevils {Bru- 

 chida) attack seeds, living in the larval state in them, such as the 

 bean weevil {Bruchus pisi). All infested seed should either be 

 steeped in carbolic water or fumigated with bisulphide of carbon 

 for some hours, when all signs of insect life will be dcstro3'ed. 



Such are some of the many ways by which wo can prevent 

 insect attack. Cleanliness and the jndicions rotation of crops will 

 to a large extent keep them in check; whilst, where we can, such animals 

 as pigs, fowls, guinea-fowls, &c., may be employed on infested land 

 after a bad attack, especially in orchards, where they will be seen 

 greedily devouring all manner of grubs that come in their way. 



Substances used for the destruction of insects, or insecticides, are 

 now employed with great success. — Insectifages are mixtures used for 

 keeping insects off a crop — preventive washes. Insecticides may be 

 liquid or dry ; the liquid washes are alwaj'S preferable to the dry 

 powders, except in one or two instances. To destroy insects by 

 washes we must carry one thing in our mind — namely. How do 

 the insects to be killed devour their food 1 are they provided with 

 a biting or sucking mouth ? 



There are six chief types of washes now in use — namely, (1) 

 Arsenical washes; (2) Resin loashes ; (.3) Paraffin washes; (4) Sid- 

 phur washes ; (5) Soft-soap and Quassia washes ; (6) Caustic washes. 



1. Arsenical washes arc three in number— viz., Paris green, London 

 purple, and arsenate of lead. These poisonous washes are only of 

 use for leaf-eating larvaj and beetles. As to the respective merits of 

 each, I incline to the opinion that arsenate of lead stands first, as it 

 ha.s a lesser tendency to burn the leafage, a feature which has too 

 often attended the use of Paris green in this country, although it 

 has met with much success in America and the colonies. The 



