!56 



INJURIOUS AND BENEFICIAL INSECTS OP CALIFORNIA. 



pear slug being a familiar example. Most of the young feed upon 

 foliage or in stems of plants, while a few make curious galls in which 

 they live. 



THE PEAR OR CHERRY SLUG 



Caliroa cerasi (Linnaeus) (Family Selandriidse) 



(Eriocampoides limacina Retzius) 



(Selandria cerasi Peck) 



(Figs. 352, 353) 



Description. — The adult is a glossy, black, four-winged insect about 

 \ inch in length. The larvae are dark olive-green, slimy and from § to 

 nearly 4 inch in length. Their work is very noticeable and consists in 



the removal of all of the 



upper green surface of the 

 leaf, causing the injured 

 areas to turn brown. Badly 

 infested trees appear 

 scorched as if by fire. The 

 eggs are oval, slightly flat- 

 tened on one side and de- 

 posited under the epidermis 

 of the leaves, usually on the 

 under sides, by the sharp 

 ovipositor of the female. 



Life History. — The eggs 

 are deposited during the 

 spring and summer (May, 

 June and July) and hatch 

 in about two weeks. The 

 larva? cut semi-circular holes 

 in the upper surface of the 

 leaves and begin to feed. 

 They are first white and 

 later become dark green, be- 

 cause of the slimy secretion. 

 The entire green upper sur- 

 face of the leaves is removed 

 by the larva? until only 

 skeletons are left. The re- 

 maining under surface turns 

 brown. When full-grown 

 the larva' crawl an inch or so into the ground and spin thin cocoons 

 in which to pupate. The first brood reaches the adult stage by the 

 middle of the summer and gives rise to a second brood, the pupa? of 

 which hibernate in the soil. The adults appear early in the following 

 spring. 



Nature of Work.— The slugs eat the green portion of the leaf from 

 ;il ove and their work is well illustrated by Fig. 353. Trees which are 

 badly infested appear brown, due to the foliage being thus killed. 



Distribution. — It is generallv distributed throughout the State. 



Fig. 352. — Pear leaf showing hatched and 

 unhatched eggs as well as the work of the larvae 

 of tlio pear or cherry slug, Caliroa cerasi (Linn.). 

 Enlarged three times. (Original) 



