DESTRUCTIVE INSECTS. 183 



European pest has now made its way into practically every 

 civilized country. It is one of the saw-flies, the adult (Fig. 

 249 a) being glossy-black and not quite so large as a house-fly. 

 These flies emerge from the ground in May and insert their 

 eggs into the tissues of the leaves from the under surface. 

 The eggs hatch in about two weeks. The dark green larva 

 (Fig. 249 b c) are snail-like in form, and their body is covered 

 with a slimy olive-colored liquid; these characteristics have 

 given them the popular and apt name of " slugs." The slugs 

 feed on the upper surface of the leaves, skeletonizing them, 

 as shown at d in Fig. 249. 



Although very sluggish in movement, the slugs have an 

 enormous appetite, and often do much damage, especially to 

 young trees. They get their growth in about twenty-five 

 days, go into the ground, and there transform in about two 

 weeks to the saw-flies. A second brood of slugs results in 

 August from eggs soon laid by these flies. 



This is a very easy pest to control. The old method was 

 to dust ashes, lime, or road-dust onto the slimy slugs, and it 

 was sometimes quite effectual ; but many of the slugs would 

 simply moult off their dusted skin and thus escape. They 

 feed so openly on the upper surface of the leaves that a dose 

 of poison can be easily included in their menu. Dust on some 

 hellebore if only a few young trees are infested, or spray in- 

 fested trees with Paris green 

 or some similar poison at the 

 rate of one pound in one hun- 

 dred and sixty gallons of water, 

 or use it in Bordeaux mixture. 



The Pear Midge {Diplosis 

 pyrivord). — This insect was 

 apparently introduced into 

 America from Europe about 

 1877, being first noticed in 

 Connecticut. It has slowly 

 spread into the near-by States, 

 and has become in many locali- 

 ties the most destructive enemy 



, ... -i i.. 1 „ Fig. 250.— The Pear Midge, a. Adult; 



to the fruit of pear; it attacks ^^ maggot; c, pupa; all much en. 

 no other fruit. larged. (Adapted from Riley.) 



