THE HEMIPTERA 37 



the mature female. The young crawl about for a while, 

 and soon become attached to one spot where they undergo 

 a series of molts and change greatly in structure. At 

 first the male and the female scale insects are very much 

 alike, but after the first molt the male scale may be dis- 

 tinguished by its smaller size and narrower shape. While 

 the female remains attached and becomes more degenerate 

 with age, the male scale insect, after passing through a 

 pupal stage, transforms into a small, graceful, winged in- 



FIG. 29. Black olive scale, la, scale enlarged. (After Comstock.) 



sect which flies from one plant to another. It has only 

 one pair of functional wings, and owing to its imperfectly 

 developed mouth parts it is incapable of taking in food; 

 after fertilizing the female it soon dies. Males are in 

 general more rarely seen than the females, and in 

 some species of scale bugs they have never been dis- 

 covered, the female probably reproducing exclusively by 

 parthenogenesis. 



The San Jose scale does a large amount of injury to 

 fruit trees. It is a particularly bad pest in California, 



