96 



BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



Table LXXI. — Time of oviposition by moths of the spring brood; observations 

 taken daily every three hours, except at 3 a. m.; Grand Junction, Colo., 1916; 

 summary of Tabic LXX. 



Num- 

 ber of 

 obser- 

 vation 

 periods. 



Period of observa- 

 tion. 



Total 



number 



of eggs 



deposited. 



Average 

 number 



of eggs 

 per ovi- 

 position 



period . 



Per cent 

 of eggs 

 deposited 

 per ovi- 

 position 

 period. 



Mean 

 tempera- 

 ture 

 during 

 ovipo- 

 sition 

 periods. 



7 

 7 

 7 

 7 

 7 

 7 

 7 



12 mt. to 6 a. m.. . 

 6 a. m. to 9 a. m... 



9 a. m. to 12 m 



12 m. to 3 p. m 



3 p. m. to 6 p. m.. 

 6 p. m. to 9 p. m.. 

 9 p. m. to 12 mt... 











10 



92 



381 



133 



32 



0.00 

 0.00 

 1.42 

 13.14 

 54.42 

 19.00 

 4.57 



0.00 

 0.00 

 1.54 

 14.20 

 58.80 

 20.52 

 4.94 



°F. 

 57.07 

 62.64 

 76.39 

 83.75 

 82.92 

 73.14 

 64.96 



m=noon; mt=midmght. 



Moths of the first brood, 1916. — Oviposition studies, similar to 

 those just described, were made with moths of the first brood during 

 a period of one week from July 24 to 31, inclusive. The results are 

 given in Table LXXII and presented in a summarized form in 

 Table LXXIII. 



The eggs were deposited in largest numbers from 3 p. m. to 6 

 p. m., with the greatest activity about dusk. With a mean tem- 

 perature of 79.28° F., from 3 p. m. to 6 p. m., over 35 per cent of 

 the eggs were laid, whereas with a lower mean temperature, 72.96° 

 F., from 6 p. m. to 9 p. m., over 46 per cent of the eggs were 

 deposited. 



It would appear from the foregoing studies that the time of day 

 is the most influential factor relating to the time of oviposition by 

 moths of the spring and first broods. The moths, as a rule, are 

 most active in depositing their eggs late in the afternoon to early 

 in the evening, their activity being greatest just about dusk. 



