46 



DECIDUOUS EBUIT INSECTS AND INSECTICIDES. 



FIRST-BROOD OF LARVAE. 



Time of hatching. — The earliest newly hatched larvae appeared in 

 the field about June 7, eggs being deposited on May 28 and the first 

 larva from the band records being collected June 27. The greatest 

 number of larvae hatched between June 17 and July 7. A few isolated 

 larvae hatched as late as July 20. 



Length of feeding period of transforming larvse. — The feeding period 

 for the transforming larvae of the first brood was determined from 70 

 individuals, as given in Table LV. The average length of feeding 

 was 21.25 days, the maximum 29 days, and the minimum 15 days. 

 These results show a shortening of the feeding period as compared 

 with the records for 1910, which must have been due to the excep- 

 tionally warm season of 1911. 



Table XLVII. — Length of feeding period of wintering larvx of the first brood, Douglas, 



Mich., 1911. 



No. 



Date of— 





No. 



Date of— 





No. 



Date of— 





of 

 ob- 





Days 

 feed- 



of 

 ob- 





Days 

 feed- 



of 

 ob- 







Days 

 feed- 

















Hatch- 



Leaving 



ing. 



va- 

 tion. 



Hatch- 



Leaving 



ing. 



va- 

 tion. 



Hatch- 



Leaving 



ing. 



tion. 



ing. 



the fruit. 





ing. 



the fruit. 





ing. 



the fruit. 





1 



June 7 



Julv 11 



34 



10 



June 22 



Julv 12 



20 



19 



June 26 



Julv 24 



28~ 



2 



June 13 



July 6 



23 



11 



June 23 



July 13 



20 



20 



...do 



Julv 28 



32 



3 



June 15 



July 12 



27 



12 



June 24 



July 12 



18 



21 



...do 



...do 



32 



4 l...do 



July 14 



29 



13 



...do 



Julv 15 



21 



22 



...do 



Aug. 3 



38 



5 June 18 



Julv 12 



24 



14 



June 26 



July 14 



18 



23 



June 27 



July 24 



27 



6 J. ..do 



Julv 23 



35 



15 



...do 



July 18 



22 



24 



...do 



Julv 30 



33 



7 i...do 



...do 



35 



16 



...do 



Julv 19 



23 



25 



...do 



...do 



33 



8 June 19 



July 19 



30 



17 



...do 



Julv 20 



24 



26 



...do 



Aug. 7 



41 



9 1 June 20 



Julv 17 



27 



18 



...do 



Julv 23 



27 



27 



...do 



...do 



41 



Average 

















28.2 



Max 



















41 

 18 







































Length of feeding period of wintering larvx. — On comparing records 

 of the feeding period of the wintering larvae with those of the trans- 

 forming larvae it will be noted that there is a marked difference, in that 

 the wintering larvse fed for a much longer period of time. The aver- 

 age for the wintering larvae is 28.2 days, the maximum 41 days, and 

 the minimum 18 days (see Table XLVII) and for the transforming 

 larvae the average is 21.25 days, the maximum 29 days, and the 

 minimum 15 days (Table LV). This difference of habit of the two 

 sets of larvae was also observed during 1910 and has been referred to 

 in connection with the studies for that year. 



About one-half of the first-brood larvae recorded in Table LV were 

 reared in bagged fruit on the trees, and the other half in fruit in cages. 



