426 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



plates. These last do not appear in any regular order. These areas 

 continue to darken for the next few days and the surface of the pupa 

 becomes wrinkled, indicating the formation of the legs, mouth-parts 

 and sclerites. Following this the abdomen and other pigmented or 

 darkened portions of the body rapidly darken and the pupa becomes 

 nearly black. 



Previous to emergence the antennae, legs and mouth-parts become 

 free and the last larval skin is kicked off and the now active insect 

 soon starts cutting and gnawing its way out. There is considerable 

 variability in the length of time it takes for the adult to emerge. Some 

 very active ones emerge in about three hours while others take a day 

 or more. In emerging, a hole is made through which the head is thrust 

 and the insect then pulls and pushes itself out, working its body from 

 side to side and forward and backward, all the time lifting and push- 

 ing with its legs. 



After emerging the parasite walks a few steps and then cleans itself 

 and straightens out its wings. The insect spends some time in this 

 way and then starts crawling about and is ready for copulation. 



Duration of the Life Cycle 



The following data are based on rearings of parasites in the labora- 

 tory at room temperatures which averaged from 68° to 72°F. 



In working out the length of the different stages of this life cycle 

 it has been found that the variability in the length of the different 

 stages indicates a very elastic life history, and one well suited for its 

 life in the host. Hence, it is impossible to give more than average 

 time lengths for the periods. ■ 



Examination of large numbers of scales, during the spring of 1914 

 at Amherst, shows that in general the scales survive the winter in two 

 forms: first, that of well-grown, first-stage scales, which when para- 

 sitized contain eggs of the parasfte; and, second, well-grown second- 

 stage scales, which, when parasitized, contain well-grown first stage 

 parasite larvse. 



It has been found by raising parasitized scales of the first stage that 

 the parasites reached maturity in from thirty-six to thirty-nine days, 

 while the parasites in the second stage scales matured in from nineteen 

 t'o twenty-three days. 



It is seen that the duration of the life cycle of those parasites raised 

 from eggs compares favorably with that of the scale, thirty-three to 

 forty days, as given by Marlatt. This is further supported by the 

 observations of Dr. H. T. Fernald and the author that the scale in 

 Massachusetts occurs in more or less distinct broods, and the examina- 



