April, '09] JOURNAL OF ECONOMIC ENTOMOLOGY * 109 



is undoubtedlj^ the average number, as evidenced by the fact that three 

 females laid 11 eggs once and 13 eggs in the following mass, while 

 another laid 10 and then 14 eggs. In all instances observed where 

 less than 11 eggs were laid at one time, or where 11 eggs were de- 

 posited two or three times in succession, the female died shortly af- 

 terward. 



The table giving the egg-laying record shows how often the egg mas- 

 ses are deposited, and it will be noticed that this time varies from two 

 to fifteen days, but an average of about four days. 



Concerning the time consumed by a female in depositing the eggs, 

 a marked regularity exists. I have watched several egg masses depos- 

 ited and find it takes about thirtj" minutes to deposit twelve eggs. A 

 quotation from notes made at the time will serve as an illustration. 



"April 15, 1908, 4 p. ni. I have just watched and timed female of 

 Pair No. 13 deposit a mass of twelve eggs. At 2.50 p. m. she was ob- 

 served in the position assumed when about to commence deposition. 

 She was apparently straining the abdominal muscles and moved the 

 abdomen up and down occasionally, during which process she fre- 

 quently stroked the tip of her abdomen with either hind leg. During 

 this process a drop of moisture appeared, probably to serve as a glue 

 for the first egg. At 2.56 p. m. the first egg was dropped, and the 

 remaining number, making a regular mass of twelve in all, were de- 

 posited from 2.56 until 3.25, when the last egg appeared, or exactly 

 twenty-nine minutes after dropping the first egg. Counting the six 

 minutes that she remained in position preparatory to laying the first 

 egg it required thirty-five minutes for the whole process. The time 

 elapsing between the appearance of each egg is almost exactly 2^/^ 

 minutes." If I had ten minutes before having to start for a train I 

 would be willing to depend on measuring that time by watching a ter- 

 rapin bug lay four eggs. Other observations have been made that 

 verify this statement. 



Incubation of Eggs 



The incubation period varies greatly with the temperature. Eggs 

 deposited from April 9 to 15 required an average of eleven days, some 

 requiring twelve days, while from May 12 to 21 the average was about 

 six days. In hot summer weather they may hatch on the fourth day. 



Egg Laying Record of Hibernated Individuals 



As already stated these observations were commenced on April 4th, 

 when a very few eggs were present in the fields. Hence, of the four- 

 teen pairs selected for the egg-laying record some may have deposited 

 one mass of eggs in the field. For this record pairs were taken and 



