The Biology of Maine Species of Altica. 163 



14 molted to the third instar in 3 days after the first molt, 53 in 

 4 days, 99 in 5 days, 22 in 6 days, 35 in 7 days, 1 in 8 days, 5 in 9 days, 

 and 4 in 11 days; average 5 days. 



Length of the third larval instar. A record which was 

 kept of 173 larvae which molted to the third instar between 

 July 1 and August 7 inclusive, may be tabulated as follows : 



13 entered the soil in 2 days after the second molt, 59 in 3 days, 

 45 in 4 days, 31 in 5 days, 15 in 6 days, 3 in 7 days, 2 in 9 days, and 5 

 in 13 days ; average 4 days. 



Length of the prepupal period. A record which was kept 

 of 141 prepupae which entered the soil between July 8 and 

 August 7 inclusive, may be tabulated as follows : 



41 transformed to pupae in 5 days after entering soil; 41 in 6 days, 

 41 in 7 days, 17 in 8 days, and 1 in 9 days; average 6 days. 



Length of the pupal period. A record which was kept of 

 148 pupae which transformed between July 13 and August 13 

 inclusive, may be tabulated as follows : 



6 emerged as adults in 5 days after the pupal molt, 21 in 6 days, 51 

 in 7 days, 57 in 8 days, 11 in 9 days, and 2 in 10 days; average 7 days. 

 Causes of variation. The extremes of variation are due 

 very largely to weather conditions. Hot dry weather favors 

 rapid development, and cool damp weather retards it. The sea- 

 son of the year has no apparent bearing on the rapidity of devel- 

 opment. There is often great variation in the time required for 

 reaching maturity from individuals all of which hatched from 

 the same tgg cluster and lived under identical conditions. 



Typical life history. The following is cited as a typical life history: 

 62 eggs deposited June 25 (1915) hatched July 3; all molted to the second 

 instar on July 7; 16 molted to the third instar on July 11, 37 on July 

 12, and 9 died in the molt ; 29 entered the soil as prepupae on July 14, 

 8 on July 15, 9 on July 16, 6 on July 19, and 1 died; 12 transformed to 

 pupae on July 19, 2 adults emerging July 26, 7 on July 27 and 3 on 

 July 28; 15 transformed to pupae on July 21, 4 emerging as adults on 

 July 27, 7 on July 28, 2 on July 29, and 2 on July 30; 15 transformed 

 to pupae on July 23, 5 emerging as adults on July 29, 5 on July 30, and 

 5 on July 31 ; 3 transformed to pupae on July 26, emerging as adults 

 on August 3; 1 transformed to a pupa on July 27, emerging as an adult 

 on August 4; 6 died before transforming. 



Seasonal History in Maine. 



The dogwood flea-beetle passes the winter as an adult hid- 

 den away in the debris at the base of the dogwood bushes. They 

 come out from their winter quarters in the spring when the 



