u 



THE SAN JOSE OE CHIXESE SCALE. 



hibernates in the nearly mature condition, as does the San Jose scale, 

 and deposits eggs in the spring or early summer. The viviparous 

 habit, or the giving birth to the living young, possest by the San Jose 

 scale, finds a parallel in many other iusects and frequently in aphides. 

 In the case of the San Jose scale the eggs are fairly well formed, 

 a few at a time, within the body of the mother. What takes the place 

 of the eofofshell consists of a verv delicate and thin membrane — the 

 amnion — which incloses the developing larva and which at the moment 

 of birth is cast off. and remains attached to or partly within the ovi- 

 duct. The amnion is probably pushed out by the next larva in turn. 



\ / 





s»^-^^iK 



^ d 





^y 







Fig. 3. — Young larva an<l developing San Jose scale {Aspidiotus peniiciosus): a. ventral view of 

 larva, showing sucking beak with seta* separated, with enlarged tarsal claw at right: b, dorsal view 

 of same, still more contracted, with the first waxy filaments appearing: c,. dorsal and lateral views 

 of same, somewhat contracted, illustrating further development of wax secretion: d, later stage of 

 same, dorsal and lateral views. sho\ving matting of wax secretions and first form of young scale. 

 All greatly enlarged ( from Howard and Marlati >. 



The difference between this mode of birth and the ordinary method 

 thru the medium of true eggs is simply that what corresponds with 

 the egg is retained bv the female until the larva is developed, instead 

 of development of the larva progressing after the egg leaves the 

 parent. 



The emergence of the young from the female over a period of six 

 weeks leads to a very confusing intermingling of generations and 

 renders it difficult to make observations on the life history except by 

 isolatincr and watchintr individuals. Rv means of such isolation of 

 individuals, however, we have been able to most carefullv trace the 



