BULLETIN 1085, U. S. DEPAKTMENT OF AGRICULTURE. 



WHERE THE EGGS ARE LAID. 



In broken or damaged corn the eggs usually are laid either in the 

 germ or in the soft starch of the endosperm, and very rarely in the 

 harder horny part of the kernels. In the case of undamaged kernels 

 eggs are laid only if the corn is very soft, as ordinarily the seed coat 

 is too tough for the weevil to penetrate. 



OVIPOSITION PERIOD AND NUMBER OF EGGS LAID. 



The preoviposition period of the broad-nosed grain weevil is ap- 

 parently a little longer than that of the other grain weevils. The 

 shortest period observed was nine days; however, it was not un- 

 common for a period of from one to two months to elapse after 

 emergence before the first egg was laid. 



The oviposition period, once started, extends over most of the 

 remainder of the life of the weevil. The longest oviposition period 

 observed was 176 days; the average was somewhat less, approxi- 

 mately 123 days. 



The number of eggs laid by the female of this species is not ex- 

 ceptionally great. The largest number laid by a single female under 

 observation was 229. These were laid over a period of 124 days — 

 August 13, 1919, to December 14, 1919, an average of almost 2 a 

 day. As shown in Table 1, the average number laid is about 136. 

 Table 1 contains data concerning the preoviposition period, the ovi- 

 position period, the number of eggs laid, and the length of life of 11 

 representative individual weevils. 



Table 1. — Oviposition data for Caulophilus latinasus. 



Weevil 

 No. 



Date weevil 

 emerged. 



Length 

 of pre- 

 ovipo- 

 sition I 

 period. 1 



Date first egg 

 was laid. 



Date last egg 

 was laid. 



Length 

 of ovi- 

 posi- 

 tion 

 period. 



Num- t 



ber of ! Date of 



eggs j death. 



laid. I 



Length 



of 



life. 



June 28,1919 



do 



Sept. 11,1919 

 Feb. 25,1920 

 May 6, 1920 

 Aug. 1, 1920 



do 



Aug. 7, 1920 



do 



Aug. 9, 1920 

 Oct. 12,1920 



Days. I 



16 I July 14,1919 



Average. 



Aug. 13,1919 

 Sept. 24, 1919 

 Mar. 27,1920 

 July 2, 1920 

 Aug. 10,1920 



do 



Aug. 19,1920 

 Aug. 20,1920 

 Aug. 31,1920 

 Oct. 24,1920 



Dec. 15, 

 Dec. 14, 

 Dec. 15, 

 Aug. 4, 

 Oct. 6, 

 Jan. 24, 

 Oct. 27, 

 Oct. 26, 

 Feb. 11, 

 Feb. 9, 

 Feb. 11, 



1919 

 1919 

 1919 

 1920 

 1920 

 1921 

 1920 

 1920 

 1921 

 1921 

 1921 



Days. 

 155 

 124 



83 

 131 



97 

 168 



79 



69 

 176 

 163 

 111 



196 

 229 

 152 



65 



156 I 

 182 



85 



68 

 160 

 127 



75 



Dec. 20,1919 

 Dec. 22,1919 

 ....do 



Aug. 13,1920 



17. 1920 

 1, 1921 

 4, 1920 

 2, 1920 



16. 1921 



Oct. 

 Feb. 



Nov. 

 Nov. 

 Feb. 



-do 



Feb. 19,1921 



176 

 178 

 103 

 171 

 165 

 185 

 96 

 88 

 194 

 192 

 131 



136 



152 



RATE OF OVIPOSITION. 



Oviposition continues throughout the year in a fairly uniform 

 manner. In the summer months the rate of oviposition averages 

 about two eggs a day, while in winter the rate drops to about one 

 per day. It is not uncommon for three and four eggs to be laid per 

 day during the summer, and in the colder portions of winter ovipo- 

 sition may cease entirely for a day or two. The greatest number 

 laid by one individual in 24 hours was six. This occurred but once. 

 Table 2 contains data concerning the rate of oviposition at various 

 times of the vear. 



