842 



Journal of Agricultural Research 



Vol. XX, No. 11 



with pith particles interwoven with silk, and sometimes in the larger cavities 

 a light cocoon is constructed, hardly more than a network of silk fibers. 

 The burrow formed in smartweed by the larvae of the first generation 

 runs upward from the entrance; and the pupal chamber, in which the 

 pupa lies head downward, is 1 or 2 inches above the exit hole. The 

 emerging moth breaks the partition and leaves the pupal envelope in the 

 chamber. In corn the cocoon is even less elaborate, and the most evident 

 difference is that the pupa lies head upward in the burrow. 



REARING RECORDS 



Eggs were easily obtained from moths collected in the field and con- 

 fined in lantern-chimney cages with a potted smartweed or in 1 -ounce 

 tin boxes containing a leaf of the same plant. The eggs hatched nor- 

 mally, and the young larvae were transferred singly to 1 -ounce tin boxes 

 for rearing. The larvae while young thrived on smartweed leaves, but 

 in later stages they preferred the stems. 



Table I contains the condensed data obtained from a series of larvae 

 hatching from eggs laid July 21 and from miscellaneous rearings from 

 partly grown larvae taken in the field. 



Table I. — Length, in days, of instars and stages of Pyrausta ainsliei 



Table II contains similar data obtained from a series of 60 larvae reared 

 individually from eggs hatching August 18. 



Table II. — Length, in days, of instars and stages of Pyrausta ainsliei 



