12 BULLETIN 535, U. S. DEPABTMENT OF AGEICULTURE. 



Table 3. — Life-history record of the horse-radish flea-beetle (luring 1916. 



Date 

 eggs 

 laid. 



Date 



larva 

 leaves 

 plant. 



Egg and 

 larval 



stages. 



Date of 

 pupa- 

 tion. 



Pre- 

 pupal 



period. 



Date of 

 emer- 

 gence. 



Total 

 pupal 

 period. 



Days. 



Egg to 

 adult. 



May 29 » 



/July 20 

 21 

 21 



24 

 24 



Days. 

 52 

 53 

 53 

 56 

 56 



July 20 

 27 

 27 

 27 

 28 

 24 

 31 

 31 

 31 

 31 

 31 

 31 

 27 

 27 

 31 



Aug. 2 

 2 

 3? 



Days. 



Died 



Days. 



6 

 6 

 3 



4 









July 31 

 31 



10 



7 



63 

 63 



Died .... 







July 27 

 27 

 27 

 27 

 27 

 27 



59 

 59 

 59 

 59 

 59 

 59 



4 

 4 

 4 

 4 

 4 

 4 



Aug. 5 

 7 

 7 

 2 



Died 



9 

 11 

 11 



7 



6S 

 70 

 70 

 66 



Died 







July 31 1 



31i 



Aug. 5 



5 



Died 





63 

 63 

 68 



68 



















Aug. 28 



28 



28 



31 



31 



31 



31 



31 



Aug. 2 



2 



2 



2 



5 



5 



5 



5 



5 



5 



60 



60 

 60 

 63 

 63 



63 

 63 

 63 

 65 

 65 

 65 

 65 

 68 

 68 

 68 

 68 

 68 

 68 



5 

 5 

 6 



8 



Died 







Aug. 5 

 13 

 13 

 13 

 13 



Died .... 





 13 

 13 

 13 

 13 



6S 

 75 



75 



75 

 75 



5 

 5 

 5 

 5 



I 



Died.... 



5 

 5 

 5 

 5 



7 



Died.... 













Died 











Aug. 7 



9 



Died 



2 



4 



Died 







Died 













Died 











Died.... 











Died 











Aug. 5 



13 



Died 





Died 







Aug. 7 

 7 

 9 

 9 

 9 

 9 



70 

 70 

 72 

 72 

 72 

 72 



6 



Died .... 













Died 











Died .... 











Died 











Died .... 













:::::::::: 



Aug. 7 

 Died .... 





70 



Aug. 13 

 13 

 13 



75 

 75 

 75 



Aug. 20 

 20 

 20 

 13 

 13 



7 

 7 

 7 





Died .... 







Died 







Aug. 20 

 Died 





83 

















Aug. 20 

 20 

 25? 





83 



83 

 881 











\ 





20 

















1 Approximate. 



SUMMARY OF TABLE. 



Average combined egg and larval stages days . . 61.4 



Average prepupal period, 30 individuals do 4. 9 



Average total pupal period, 12 individuals do 10 



Average egg to adult, 20 individuals do 71.8 



OTHER RECORDS. 



Appearance record: First observed on leaves of horse-radish just breaking through the ground at Green 

 Bay. Wis., April 20, 1916. 

 Copulation first observed May 2. 



RECENT INJURY. 



An account of recent injury b} r the horse-radish flea-beetle was 

 received from a correspondent at Shermerville, 111., who wrote Janu- 

 ary 3, 1917, substantially as follows, and who, later, furnished 

 specimens : 



T should like your advice on an insect which destroys my horse-radish. It is 

 causing thousands of dollars loss every year in tins community, and there seems 



