THE BLACKHEAD FIREWOEM OF CEANBEREY. 



19 



32 males and 42 females of the first generation were collected from a 

 cranberry bog on July 15, 1918, and immediately confined as follows 

 in three battery jars 9 inches high by 5 inches wide: Jar No. 1 con- 

 tained 12 males and 12 females; jar No. 2, 10 males and 12 females; 

 jar No. 3, 10 males and 18 females. Each jar was provided with a 

 few inches of slightly moist sand on the bottom, an abundance of 

 clean cranberry uprights, and a sponge moistened with a weak solu- 

 tion of sugar and water for food and moisture, 



Every 3 hours from 2 a. m. to 9 p. m. daily until July 20 the up- 

 rights in each jar were replaced with fresh ones and the eggs on them 

 and on the side of the jar counted and recorded. The sponge was 

 also moistened daily. 



The number of eggs found deposited at each examination is sum- 

 marized in Table 2. As will be noted therein, eggs were laid during 

 every period between examinations, but the largest number of eggs 

 was deposited between 3 p. m. and 9 p. m., 663, or 39.6 per cent of 

 the total, being deposited between 3 and 6 p. m., and 650, or 38.8 per 

 cent, between 6 and 9 p. m. The smallest numbers were deposited in 

 the 12-hour period between 9 p. m. and 9 a. m. It will be noted fur- 

 ther that the time of day during which eggs were deposited in largest 

 numbers is also the period of greatest activity on the bog. 



Table 2. — Number of eggs of blackhead fireworm moth deposited every 3 hours 

 from 6 a. m. to 9 p. m. by moths of the first generation confined in battery 

 jars; Seaview, Wash., July 15 to 20, 1918. 



Period of deposition. 



Number 



of eggs 



deposited. 



Per cent 



of total 



deposited. 



Period of deposition. 



Number 



of eggs 



deposited. 



Per cent 



of total 



deposited. 



9 p. m. to 6 a. m 



78 

 ' 8 



67 

 209 



4.6 



.5 



4.0 



12.5 





663 

 650 



39.6 



6 a. m. to 9 a. m 



6 p. m. to 9 p. m 



38.8 





Total 





12 noon to 3 p. m 



1,675 



100.0 









The number of eggs found deposited at each examination is shown 

 in graphic form in figure 10, together with a curve showing the hourly 

 temperature during the period of the experiment. Attention is here 

 drawn to the influence of the temperature on egg-laying. It will be 

 noted that the largest number was deposited between 3 and 6 p. m. on 

 July 16, a few hours after the highest temperature, namely, 75° F., 

 was recorded. 



SEASONAL HISTORY. 



It was noted that larvae of the first generation appeared in greatest 

 abundance on the bogs about the latter part of May, the pupae toward 

 the middle of June, and the moths about the first or second week 

 in July. 



