522 



Journal of Agricultural Research 



Vol. VI, No. 14 



Table IV .—Daily feeding record of II larva of Chrysopa calif ornica at Tempe, Ariz., in 



October, 1915 a 



a to, Date of molting; c, date ol spinning cocoon. 



Table III shows the record of 15 larvae during the month of February 

 and Table IV shows the record of 1 1 larvae during the month of October. 

 It will be noted that both the daily and total consumption were much 

 larger during the latter and warmer period than 

 during the former and that the total feeding period 

 was nearly half the length during this period. 

 Only full-grown wingless specimens of Aphis maidis 

 were used in this experiment. 



When the larva gets ready to molt, it settles 

 down in some protected spot and rests for a period 

 Fig. 5— Chrysopa caiifornka: of several hours, of ten a day or more, and when the 

 Pupa case. opportune time seems to have arrived it begins a 



series of movements, mostly of a rising and falling nature, calculated to 

 burst the skin on the back. When this is finally accomplished, it crawls 

 out and, after a few minutes' rest, is the same vora- 

 cious creature it was before except only that its size is 

 greater than in the preceding instar. 



During the first and second instars, after the larva 

 has eaten its quota of aphids, it rests, often as long as 

 two days; during the last instar, however, this rest 

 period is not apparent, owing to the fact that it takes 

 place within the cocoon previous to pupation. 



As shown by dissections of several cocoons, this 

 resting period, during which the pupa is forming within the larval skin, 

 is from 6 to 9 days in length. Later in the observations it was discov- 

 ered that one could tell by external indications just when this change 



Fig. 6. — Chrysopa cali- 

 f ornica: Pupa. 



