SOME SCALE INSECTS. 87 



.a general thing, the female casts its skin from three to five times 

 before reaching the adult condition, and beginning to lay eggs or 

 give birth to young. With each successive molt the insect in- 

 creases in size and becomes usually more convex in form. Its 

 legs and antennae become proj^ortionately reduced, and its eyes 

 become smaller and are finally lost. As a general thing it is in- 

 capable of moving itself after the second molt, from the spot 

 where it has fixed itself, although certain species crawl through- 

 out life. The adult female insect, then, is a motionless, degraded, 

 wingless, and, for all practical purposes, legless and eyeless crea- 

 ture. In the armored scales she is absolutely legless and eyeless. 

 The mouth parts, through which she derives nourishment, remain 

 functional, and have enlarged from molt to molt. Her body 

 becomes swollen with eggs or young, and as soon as these are 

 laid or born she dies. 



The life of the male differs radically frouL that of the female. 

 Up to the second molt the life history is practically parallel in 

 both sexes, but after this period the male larva transforms to a 

 pupa, in which the organs of the perfectly developed, fledged in- 

 sect become apparent. Tliis change mav be undergone within a 

 cocoon or under a male scale. The adult male, which emerges 

 from the pupa at about the time when the female becomes full 

 grown, is an active and rather highly organized creature, with two 

 broad, functional wings and long vibrating antennae. The legs 

 are also long and stout. The hind wings are absent, and are re- 

 placed by rather long tubercles, to the end of each of which is 

 articulated a strong bristle, hooked at the tip, the tip fitting into 

 a pocket on the hind border of the wings. The eyes of the male 

 insect are very large and strongly faceted. The mouth parts are 

 entirely absent, their place being taken by supplementary eye 

 spots. The function of the male insect is simply to fertilize the 

 female, and it then dies. The number of generations annually, 

 among bark lice, differs so widely with different forms that no 

 general statement can be made. 



As a general rule scale insects have been divided, both from 

 the classificatory standpoint and from the standpoint of practical 

 remedial treatment, into those which are armored or secrete 

 scales over their bodies, and those which are naked and have no 

 differentiated scale. From the practical standpoint, however, 

 this division is of no great use, since even the so-called naked 



