without the aid of a hand lens, crawhng here and there on the in- 

 fested plants in an effort to find a siiital^le ])lace for settlement. The 

 young insect is active for some hours but soon settles, pushes its 

 slender, threadlike beak into the plant, and begins to feed by sucking 

 out the sa]). After this there is no further movement from ])lace to 

 place, and the waxy covering, which often begins to develop l)efore 

 the insect has settled, soon covers it completely. 



In about twelve days the insects molt and from this time on the 

 male and female scales may be readily distinguished. Eight or ten 

 days later the males change to pupa?, and in from twenty-four to 

 twenty-six days from birth the adult males emerge and fecundate 

 the females, which in turn reach maturity and begin the production 

 of young in from thirt3"-three to forty days from birth. An individual 

 female may give birth, on the seasonal average, to about 400 young, 

 and as the life cycle of the female covers but a few w^eks there may 

 be several generations a year, the nund:)er varying according to lati- 

 tude. The progeny from one parent during the season have been 

 estimated at 1,608,040,200 females. It is thus easy to understand 

 how the insect can so quickly destroy the i)lants infested and why 

 prompt remedial measures are so necessary. With the a})proach of 

 the cool weather of fall, breeding graihially ceases and the scales in 

 all stages enter hibernation. Most of the older and also most of the 

 younger individuals perish during the winter, the survivors being 

 those about one-third or one-half grown, as stated. 



MEANS OF DISTRIBUTION. 



The San Jose scale is (Hstri])uted from one region to another prin- 

 cipally on nursery stock, scions, or budding and grafting materinl. 

 Tlie danger of its dissemination in this way is fully realized, an<l laws 

 are in force in the majority of States requiring the inspection of 

 nurseries and the destruction of infested stock. Traffic in nursery 

 ])roduce is j)ermissible only under the certificate of an official ento- 

 mologist or inspector that the stock is free from the scale. In addition 

 to the actual inspection of nurseries, further safeguard is furnished 

 by tlie practice of most nurserymen (com])ulsory in some States) of 

 fumigating the i)lants, before distribution, with hydrocyanic-acid gas. 



After the insect once becomes established in a locality its spread 

 is accomjdished by various agencies. As exj)lained under the 

 natural history of the insect, it is capable of movement only during 

 a short period after l)irth. During this crawling stage the insects 

 are able to pass from tree to tree where the limbs are in contact. 

 But it is by agencies inde})endent of itself that it is ])rincipally 

 distributed. Prominent among these factors are birds, which may 

 alight u])()n infested trees, where the young insects may crawl uj)on 



[Clr. ll.'4] 



