422 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



NOTES ON THE LIFE HISTORY OF PROSPALTELLA PER- 



NICIOSI TOWER 1 



By Daniel G. Tower, M. Sc, Amherst, Massachusetts 



Introduction 



The following notes were taken during the early spring, fall and 

 winter of 1913, and the spring of 1914. 



This parasite, a description of which, both male and female, was 

 published in the Ann. Ent. Soc. Am., vol. VI, No. I, pp. 125-126, is a 

 true internal parasite, the larval forms living within the body tissues 

 of its host, the female San Jose scale, Aspidiotus perniciosus Comst., 

 except during the last part of the second larval stage as at this time 

 the entire contents of the host are consumed by the larva, which, 

 after passing its waste, pupates in the empty skin of the scale. 



Both male and female parasites emerge from the empty skins of 

 second-stage and early third-stage female scales, but by far the largest 

 number emerge from second-stage scales. 



The following description of the life cycle of the parasite, which has 

 been worked out, is that of a parasite maturing in and emerging from 

 a second stage scale. No doubt the development of those which 

 emerge from third stage scales is the same. 



The Egg 



Developed eggs are readily seen Avithin the abdomen of the female 

 parasite when examined under the microscope at the time of emergence, 

 and many are even fully developed in the late pupal stage. They can 

 also be examined as found in the bodies of first-stage and early second- 

 stage scales. 



The egg is ovate and has a distinct micropyle at the smaller end. 

 The chorion is smooth and hyaline and the nucleus, located at the 

 larger end, and the opaque granules, with which the egg is filled, show 

 through. 



The egg measures .085 mm. in length and .04 mm. in width. 



The number of eggs deposited by an individual is not known, but 

 1,364 developed eggs were obtained from twenty females selected as 

 they emerged, giving an average of sixty-eight developed eggs apiece. 

 Of the twenty females examined, the smallest and largest number of 

 eggs found in a single specimen was forty-six and 102, respectively, 

 and in most of these females there were still undeveloped eggs. 



^ Contribution [from the Entomological Laboratory, Massachusetts Agricultural 

 College. 



