412 Journal of Agricultural Research voi. xx, no. 6 



proboscis. The cavity is trimmed and enlarged and the sides smoothed off 

 until the weevil is satisfied that all is as it should be. She then with- 

 draws her proboscis and turning around swings the abdomen about until 

 the egg cavity is located. The ovipositor is then thrust into the cavity 

 and a single egg is deposited. 



Before the ovipositor is withdrawn a translucent mass of material is 

 discharged on top of the egg and is tamped down level with the surface of 

 the kernel of corn, forming a protective cap to the egg. This cap, because 

 of its translucent character, assumes the color of the portion of the kernel 

 in which it is located, thereby making the discovery of the egg difficult at 

 times. Occasionally one or more extra discharges are made on top of the 

 first cap, causing the cap to protrude above the surface of the kernel. 

 These latter discharges are usually irregular, opaque, and mixed with 

 fecal matter. 



The time taken to excavate the egg cavity varies with the condition of 

 the grain. When the corn is soft the cavity may be completed in less 

 than 30 minutes, whereas in hard corn the operation may take as long as 

 2 hours. The actual time of depositing the egg after the cavity is finished 

 is short, from 3 to 4 minutes on the average. 



WHERE THE EGGS ARE PLACED 



The egg cavities are made usually in some part of the soft starch of the 

 grain or in the germ, where the work of excavation is easier and the 

 young larva upon hatching will have an abundance of food ready for 

 instant use. Frequently in kernels of corn that have not sufficiently 

 hardened numerous excavations will be made only to be abandoned by the 

 weevil as unfit for use, the weevils apparently having the instinct of 

 knowing when the corn is unfit to maintain larval life. Several eggs are 

 often deposited in the same kernel of corn, though when the supply of 

 grain is abundant it is not usual for a weevil to deposit more eggs in a 

 single kernel than can mature in the limited amount of food present. 

 When weevils are confined with only a few kernels, however, the instinct 

 to continue laying eggs predominates and eggs are deposited in all parts 

 of the grain. 



The egg itself is somewhat flexible in character and conforms to the 

 shape of the egg cavity. It is placed with the top just below the surface 

 of the kernel and with the larger end toward the inner end of the cavity. 



RATE OF OVIPOSITION 



The rate of oviposition varies with the condition of the grain, the age of 

 the weevil, and the temperature. During the warm weather of summer, 

 with young female weevils and with corn in the "hard gum" stage, the 

 oviposition rate reaches its maximum. Under such conditions from 8 to 

 10 eggs are laid per day, though as many as 20 to 25 may occasionally be 

 laid in a like period. 



