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



The frequency of hatching for the combined lots is approx- 

 imately shown in figure 8. Although more of the eggs were 

 deposited during the first three hours (first half) of the period 

 of deposition, the majority (82%) hatched during the last half 

 of the period of hatching. 



As stated, the length of the period of deposit when relatively 

 short appears to be unrelated to the duration of the period of 

 hatching or to the duration of the period of embryonic develop- 

 ment either. The data probably, are insufficient to show the 

 general tendency, yet the period of batching was as long for some 

 of the lots as for the lots combined. It may be noted further 

 in regard to the latter, that the eggs of the first five lots deposited 

 during the first half — approximately — of the whole time, began 

 to hatch 24 hours earlier than those eggs of the remaining lots 

 which were deposited during the last half of the whole period of 

 deposition. And this was "correlated" with bimodal and 

 "normal" frequencies of hatching for the two groups ; yet the 

 relations of these "correlations',' are not apparent. Just why the 

 random, chanced or accidental groups of eggs obtained in suc- 

 cession at short intervals of time over a relatively short period 

 (.25 day) should show grouping into halves (in regard to the 

 period of deposit) in relation to frequency, first hatching and 

 distribution of frequency is obscure from the data. Moreover, the 

 table brings out a substantial increase in the duration of the period 

 of embryonic development and noticeable decreases in the range 

 of variation for the period of hatching. These are pointed out, 

 not explained. 



It was found therefore, that man)- eggs of similar parentage 

 deposited in rapid succession for short periods of time, as in the 

 cases cited, hatch at random after a certain period of time, and 

 that any single one of them is as likely to hatch at one time as 

 another within the limits of the whole period ; that two (or more) 

 lots of eggs deposited in short successive periods of time vary in 

 regard to the beginning of hatching in all of the lots, yet without 

 affecting the actual duration of the period of embryonic develop- 

 ment, — that is, the duration of the period of hatching is variable 

 under such conditions ; and that lots of eggs deposited continu- 

 ously (in succession) for 362 minutes during periods varying 

 from .25 to 120 minutes, required for hatching a period no longer 



