70 BULLETIN 429^ U. S. DEPARTMENT OF AGRICULTURE. 



THIRD BROOD OF LARV.E. 



LengtJi of feeding period. — In Table L are also found the records on 

 the length of the f eedmg period of transf ormmg larvae of this genera- 

 tion. Of the 180 individual insects under observation in this con- 

 nection the results show that 31 of the number completed the stage 

 within 18 days. The maximum number of feeding days is 28, the 

 minimum number 15, and the average is 20 days for the whole 

 series. This average is found to be somewhat greater than the cor- 

 responding average for the second brood, but is 4.45 days shorter 

 than the same time for the first brood. 



Feeding period of wintering larvse. — Of the 722 larvae of the third 

 brood under observation in this connection, 542 or 75.06 per cent, 

 were found to be wintering larvse. The maximum length of the 

 feeding period of the wintering larvse was 35 days, as contrasted 

 with the maximum of 28 days, which is the longest corresponding 

 period for transforming larvae of the same brood. The shortest 

 feeding period recorded is 14 days, while an average of 21.1 days ex- 

 ceeds the average period for the transf ormmg larvse by only 1.1 

 days. See Table LI. 



