The Bulletin. 9 



insect lias crawled about for an hour or so it becomes hungry and inserts 

 its slender, delicate beak into the tender bark and begins to suck the sap. 

 Then the scale begins to form over its body. At first it is of the same 

 oblong shape as the body of the young insect, and whitish, as shown in 

 the center of the figure, at the top. Then the scale becomes more rounded, 

 and as it grows it becomes darker, until it is dark gray or almost black. 

 Once the scale begins to form over the body the insect remains attached 

 to the bark at that spot. 



The Full-grown Insects. — The full-grown female insects always remain 

 under their circular scales and there give birth to their living young, for 

 this species does not lay eggs as is the case with most insects. The males, 

 on the other hand, finally develop into tiny two-winged fly-like insects, 

 but in consequence of their sex they cannot play much part in spreading 

 the insect, as young can only be born where females are present, and these 

 as we have stated remain attached to the twigs. 



The Life-history of the Insect. — Many points in the life-history have 

 already been mentioned. The females begin to give birth to living young 

 in the spring. In this the San Jose Scale is an exception to the rule 

 among insects, which in most cases lay eggs. At Raleigh, breeding begins 

 from March to May, depending on season. After crawling for a short 

 time the young insects insert their beaks and begin to feed. Then the 

 skin is shed and the scale begins to form over the body and the insect is 

 thus confined at that spot. When the skin is shed, the legs, eyes and 

 antennas (feelers) are shed off with it, and thereafter the female insect 

 is always eyeless, legless and wingless ; simply has the organs for taking 

 and digesting food and for reproduction. It takes the females from 

 thirty to forty days to reach maturity and the males not quite so long. 

 The male develops finally into a tiny, yellowish, two-winged flying insect. 

 Strange to say, the mature male insect has no mouth for taking food, the 

 position of that organ being occupied by an extra pair of eyes. This ren- 

 ders it more proficient in finding mates and thus aids in the multiplica- 

 tion of the species. In this State there are probably from five to eight 

 generations in a season, and the number of progeny of a single fertile 

 female, in the course of a season, if there were no fatalities, would by 

 actual calculation number among the hillions. Remembering that many 

 of the insects are destroyed by enemies as described later, we can still see 

 that it is no wonder that a tree that becomes infested while young is 

 almost sure to die unless thoroughly and persistently treated. The most 

 active period of increase is during August and September. Enlarged 

 illustrations of the different stages of the San Jose Scale are shown in 

 Fig. 3, which appeared in a Bulletin of the U. S. Dept. Agr. just before 

 this Bulletin goes to the press.* 



♦Farmers' Bulletin 650, "The San Jos6 Scale and Its Control," by A. L. Quaintance. 



