574 



Journal of Agricultural Research 



Vol. XIII. No. II 



The only female reaching maturity (No. 29 in Table I) passed through 

 six molts, aside from which nothing unusual was observed about her life 

 cycle. There is slight chance for error, as the exuviae in all cases were 

 examined with a powerful magnifier. 



Data were secured from other nymphs which remained under obser\^a- 

 tion for only a portion of their life cycle, and during this period the 

 average length of each instar was computed from these data on the basis 

 of a much larger number. This is done in Table II which gives the aver- 

 age length of instars for the false chinch bug at Garden City. 



TablB II. — Average 1-ength of nymphal instars of Nysius ericae, Garden City, Kans., 



1914 



Thus calculated, the length of the nymphal period is 20.35 days. 

 Data on the number and length of instars which were secured at 

 Wichita during the rearing work of 191 6 are presented in Table III. 



Table III. — Number and length of nymphal instars of Nysius ericae, Wichita, Kans., 



1916 



Specimen No. 



76. 

 149 

 250 



Number of days in each instar. 



First. Second. Third. Fourth. Fifth 



Sex. 



Female . 



Male 



..do.... 



Length 



of 



njTnphal 



life. 



18 

 37 



28 



Other data secured during 1916 permit averages to be presented for 

 each instar with numbers as in Table IV, which gives the average length 

 of instars for the false chinch bug at Wichita. 



Table IV. — Average length of nymphal instars of Nysius ericae, Wichita, Kans., igi6 



This gives the length of the nymphal period as 20.69 days. 



Tables I and III indicate great variation in the duration of the 

 instars, both actually and relatively in proportion to the length of 

 the entire nymphal period. The record of No. 29 in Table I indi- 



