June 19, 1916 Feeding Parasitized LarvcB of Cirphis unipuncta 457 



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LIFE CYCLE OF THE PARASITE 



The biology of A. militaris has already been studied and the results 

 published.^ 



Oviposition took place with great rapidity and apparently anywhere in 

 the host, attempts even being made by the parasite to oviposit in the 

 head. The largest number of eggs inserted at one time, according to 

 the observations herein recorded, was 154 for 3 ovipositions, averaging 

 51 + each (Table I, Experiment 23). The two endoparasitic stages and 

 the egg stage required an average of 14 days, 1 1 }i minutes, while the time 

 spent by the third larval stage and the pupal stage in the cocoon averaged 

 9 days, 8 hours, and 45 minutes, and the average for the total life cycle 

 was 23 days, 12 hours, and 26 minutes. 



The parasitic larva leaves its host by means of an individual exit 

 hole cut through the muscles and epidermis by its mandibles. As the 

 larvge squeeze through the holes they molt their second larval skins, and 

 when about two-thirds of their way out commence to spin their cocoons. 

 After the cocoon is spun and previous to pupation, the accumulated 

 wastes are passed, being deposited at one end of the cocoon. Shortly 

 following this the larva pupates and the last larval skin is pushed to the 

 same end of the cocoon. 



The adult issues, after kicking off its pupal skin, by cutting off a cap- 

 like portion at one end of the cocoon, cleans itself, and at the same time 

 passes a quantity of waste. It is now ready for copulation, oviposition, 

 or feeding, as the case may be. In this respect it was found that females 

 were at once ready to oviposit following emergence and previous to feed- 

 ing or copulation, and that the progeny from such females were all males. 

 Hence it is seen that unfertilized females give rise parthenogenetically 

 to a generation of males. 



CONCLUSIONS 



In using the data compiled by Davis and Satterthwait on the amount 

 of food eaten by healthy larvae of C. unipuncta, for comparison with the 

 amount eaten by parasitized lar\^ae, it will only be necessary to use the 

 feeding records for the last three instars in one series of their experi- 

 ments, this being the one in which the larvae were confined in lantern- 

 globe cages. These records were selected in preference to those obtained 

 by keeping the larvae in large vials, because in the former case a larger 

 number of records were obtained, although in the latter case the averages 

 of the feeding records for the same periods run higher. 



Larvae 10, 11, 15, and 16 were newly molted fifth-stage specimens 

 when oviposited in, and they ate 16.21, 12.16, 11.97, and 14.50 square 

 inches of com foliage, respectively, during their last two stages previous 

 to the emergence of the parasites, which is a much smaller amount than 



' Tower, D. G. Biology of Apanteles militaris. In Jour. Agr. Research, v. s, no. la, p. 493-308, i fig., 

 pi. 50. 191S. 



