AN INTERNAL PARASITE OF THYSANOPTERA. 



45 



Freize tliorm()graj)h. Tlio observations covering the life-history 

 studies of the parasite were matle during the months of July, August, 

 and September. 



LENGTH OF TIME FROM OVIPOSITION TO FIRST INDICATION OF 



PARASITISM. 



Because of the very minute size of this insect and tlie internal life 

 led by it in the larval stage, the length of the egg and larval stages 

 was not separately determined. The time required from oviposition 

 by the adult parasite until parasitism becomes evident in the host 

 may be 5 days as a minimum or 17 days as a maximum, but by far 

 the greater number require from 7 to 12 days for this. In Table V 

 this period is recorded for a series of 19 experinK^nts. 



Table V. — Time between oviposition and first indication of parasitism, by Thripoctenus 



russelli. 



The diagram, figure 8, gives the length of time between oviposition 

 and indication of parasitism for 353 s|)ecimens. 



LENGTH OF TIME FROM OVIPOSITION TO PUPATION OF THE PARASITE. 



The length of time from oviposition to pupation of the parasite, or 

 the period covered by the egg and larval stages, was carefully deter- 

 mined for 241 specimens and varied from 8 days, as a minimum, to 

 19 days as a maximum; but 13 or 14 days are required by the 

 greater number of individuals. Figure 9 shows this })eriod. 



As the length of the pupal stage was taken up in the discussion of 

 the pupa (p. 33) it is not again referred to here. 



