2OO 



Commercial Gardening 



caterpillar is overpowered with the maggots of the Ichneumon Flies; while 

 on the right a caterpillar is covered with their cocoons. Amongst the prey 

 of these Ichneumon maggots may be mentioned the Cabbage Butterfly, the 



caterpillar of the Death's Head 

 Moth, the various kinds of 

 aphides, wire -worms, and no 

 doubt other grubs. There are 

 so many kinds of Ichneumon 

 Flies, all helpful to the gar- 

 dener, that it becomes a difficult 

 problem to know them from 

 the enemies. Fig. 159 shows 

 an Ichneumon Fly highly mag- 

 nified, and it will be observed 

 that it bears a resemblance to 

 the wasps and bees. 



Laeewing' Flies. These 

 flies belong to the genus Chry- 

 sopa, and, as may be seen from 

 fig. 161 (1), derive their name 

 from the delicate veining of 

 their wings. The eyes are 

 golden green, very large and 

 conspicuous, with two long, 

 slender feelers on the head. 



The female is about | in. long and larger than the male. The larvae shown 

 at 3 and 4, in fig. 161, are very voracious, and will devour large numbers 

 of aphides, including American Blight, in a very short time, and will even 

 attack caterpillars about f in. long. These hairy larvae develop from eggs 



that are laid singly on hair-like 

 stalks in rows and clusters, as 

 shown in fig. 161, at 2, these 

 slender stalks often projecting 

 about 1 in. from the surface of 

 the leaves or branches to which 

 they are attached. After the 

 larvae have fully developed they 

 change into pupae and reach the 

 perfect-insect stage in about three 

 . _. weeks during the summer months. 



1, Chrysopa perla. 2, Eggs. 3, Larva. 4, Larva magnified. 



5 and 6, Cocoon (natural size and magnified). The later broods pupate during 



the winter months in cocoons, as 

 shown at 5 and 6 in fig. 161, and become perfect in spring. 



Ear-shelled Slug*. Although most slugs are injurious to vegetation, 

 there is one genus which provides flesh-eating slugs that will feed upon 

 other slugs and even worms. The British Ear-shelled Slug (Testacella 



Fig. 160. Caterpillar devoured by the Larvae of Ichneumons, 

 and Caterpillar covered with their Cocoons 



Fig. 161. Laeewing Fly 



