INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



407 



Life History.— The eggs are deposited upon the leaves after the 

 trees have put forth a good growth in early summer, May and June. 

 The young caterpillars are gregarious in habits, feeding in compact 



colonies, and are thickest dur- 

 ing June and July, but may con- 

 tinue to appear until late in 

 September, showing that eggs 

 are often laid quite late. Their 

 work consists in destroying the 

 foliage, the midribs of the 

 leaves being all that usually re- 



Fig. 410. — The larvae of the red-humped 



caterpillar, Schizura concinna (S. & A.), and 

 their work on apple. Natural size. (Original) 



Fig. 4 1 1. — Adul t of the red- 

 humped caterpillar, Schizura 

 concinna ( S. & A.). Enlarged 

 twice. (Original) 



main. They feed rapidly and 

 thoroughly, making the attacks 

 easily discovered by a careful 

 observer. Late in July and dur- 

 ing the months following many 

 of the larva? become full-grown 

 and drop to the ground, where 

 they spin a thin cocoon and 



hibernate. The cocoons are located from one to three inches under 

 the surface of the ground, among the thickly fallen leaves, or in the 

 grass, if it is allowed to grow in the orchard. The winter is passed 

 in the larval stage, the pupal stage occurring in early spring, the 

 adults emerging soon after to lay eggs when the foliage is well out. 



Nature of Work. — The caterpillars feed only upon the foliage. 



Distribution. — This introduced species occurs in the central part of 

 the State. 



Food Plants. — Among the food plants are apple, apricot, aspen, 

 blackberry, cherry, hawthorn, huckleberry, pear, plum, prune and 

 willow. 



Control. — Entire colonies may be exterminated by hand picking, 

 which is especially recommended for small trees. In large orchards, 

 where this is impossible, arsenical sprays should be used. Hoeing or 



