86 Trans. Acad. Sci. of St. Louis 
Bergtold’s (1917) record of 11 to 14 days is given on the au- 
thority of MacDonald. In one ease in the writer‘s experience 
incubation extended for a known period of fourteen days but for 
some unknown reason the nest was deserted, apparently, for two 
days after incubation had begun (the eggs were cold), and this 
probably accounts for the unusual period. Considering eleven 
TABLE 10 
Reactions of the Prairie Horned Larks to man when eggs were in the nest, 
at Evanston, Ill., 1926. 
Nest No. No. of Visits | No. of Times | No. of Casual |No. of Distress| No. of Other 
Parent Noted |Abandonments| Simulations Reactions 
3 9 5 1 2 2 
5 4 0 1 3 
6 5 5 4 0 1 
7 9 6 2 2 2 
8 4 3 1 1 1 
9 14 8 7 0 i 
10 11 3 4 0 1 
11 10 8 1 5 2 
12 8 6 3 1 2 
13 10 8 3 1 : 
14 11 8 5 1 3 
15 11 il 5 0 - 
19 11 & 6 1 i 
20 5 4 3 0 fp. 
21* 12 p 
10 8 0 B2 
sa : ; ‘ 0 % 
pees 
Total 055-3. 142 105 59 15 = 
SpE apr emer ee ad ee 
days the optimum I have used it as the basis for estimation of 
all the tables and figures where dates of egg-laying and nest- 
building are given. 
_Though Bendire (1895) and Criddle (1917) say the male as- 
sists in incubation (Criddle does not specify incubation but 
Says “relieving the female upon the nest’’), I have no 
evidence that the male ever incubates or broods. I have de- 
termined the sex upon hundreds of visits to many different 
