12 DEPARTMENT BULLETIN 119. 



In observations on the hatching of 8 individual nymphs, the time 

 required for emergence varied from 14 to 40 minutes, the average 

 being 20 minutes. The newly hatched nymph is capable of locomo- 

 tion soon after completing emergence but generally remains on or 

 near its parent egg cluster until the second instar is reached. All 

 normal eggs in the same egg cluster generally hatch within a 24- 

 hour period. 



PEOPORTION OF EGGS HATCHING IN THE FIELD. 



Unless destroyed by parasites or predacious enemies, the propor- 

 tion of eggs of Chlorochroa sayi hatching in the field is very high. 

 Occasionally a few eggs in otherwise normal clusters were prevented 

 from hatching by being deposited wrong end up. A few eggs, too, 

 were deposited on top of the main egg cluster, which invariably 

 prevented the lower eggs from hatching. Very few infertile egg 

 clusters were collected in the field. Abnormal weather conditions 

 prolonged the period of incubation but appeared to have no other 

 injurious effects on the eggs. 



PEOPORTION OF EGGS HATCHING IN THE LABORATOBT. 



In one laboratory experiment a total of 1,068 eggs were deposited 

 by 30 females confined in life-history cages. Of this number a total 

 of 981 eggs, or 91.88 per cent, hatched. The remaining 8.12^ per cent 

 were probably somewhat affected by the abnormal cage conditions. 



NYMPHS. 



DURATION OF NYMPHAL STAGES. 



The prevailing temperature conditions have a marked influence 

 in controlling the duration of the nymphal stages of Chlorochroa 

 sayi in the field and in life-history cages. During the period from 

 July 5 to August 18, 1916, a total of 17 nymphs were reared from egg 

 to adult. (See Table II.) In this series of cages the first instar 

 occupied 5 days ; the second instar, from 7 to 9 days with an average 

 of 8.2 days; the third instar, from 5 to 7 days with an average of 

 6.4 days; the fourth instar, from 7 to 10 days with an average of 

 8.2 days; and the fifth instar occupied from 13 to 17 days, the 

 average being 14.9 days. From 42 to 44 days were required to com- 

 plete the nymphal period, the average being 42.7 days. 



