14 



Bulletin Wisconsin Natural History Society. [Vol. 8. No. 1. 



after 12 hours, 14 (31.1%) had hatched, but none did so in the suc- 

 ceeding 7 hours; during the next 13 hours 23 more (51.1%) hatched 

 and the total was completed by the hatching of the 8 (17.7%) re- 

 maining eggs during the next 6 hours. Here, the period of hatching 

 extended to 37 hours or 36 1 /, hours over the period of deposition. 

 The curve of distribution shows about the same facts as shown for 

 lot No. 1. (See figs. 1 and 2.) 



Lot No. III. Sixty-seven eggs deposited in a similar manner during 

 a period of 20 minutes (11 :40 a. m. to noon) began to hatch at 11 P. M., 

 August 31st, or at the same time as the previous lots ; after 9y 2 hours, 

 20 (29.7%) of them had hatched; after 12 hours, 2S (41.8%) had 

 hatched ; then followed a period of 9 hours during which none hatched ; 

 then during the next 11 hours 30 (44.7%) more had hatched and 

 hatching (13.4%) was completed during the next 10 hours. The period 



^ 



'/x ' 



Figure 3. — 67 observations. Figure 4. — 97 observations. 



of hatching here extended over 41 hours, 40y 2 hours longer than the 

 period of deposition. The curve of distribution is shown approximately 

 in figure 3. 



Lot No. IV. Ninety-seven eggs deposited similarly in a period of 

 45 minutes (noon to 12:45 p. M.) began to hatch at about the same 

 time as the previous lots and after 9y 3 hours but 9 (9.27%) of them 

 had hatched; after 12 hours. 20 (20.61%) had hatched; then followed 

 a lapse of 10 hours; during the following 10 hours 68 (70.1%) more 

 of the eggs hatched and hatching (9 eggs or 9.27%) was completed 

 in 8 more hours, making a period of hatching- of 40 hours, over 39 

 hours longer than the period of deposition. The curve of distribution 

 is shown in figure, 4. 



Lot No. V. Two hundred and fifteen eggs deposited similarly 

 during a period of 90 minutes (12:45 to 2:15 P. M.) began to hatch 

 at approximately the same time as those in the previous lots and after 

 9% hours 10 (4.65%) had hatched; after 15 hours 25 (11.62%) of 



