Nov., 1911 
RELATION OF BIRDS TO AN INSECT OUTBREAK 
199 
mate and lay their eggs in the fall, but more often they live through the winter and 
lay their eggs in the early spring (see fig. 68). 
Ill 1902 this same species of butterfly was abundant in the north. Since that 
time it has not been seen in any great numbers until this year. In the memory of 
the oldest inhabitants of Siskiyou County, the numbers of butterflies this year far 
exceed those of any previous year. The newspaper accounts were often exagger- 
ated, and yet few people who did not see the swarms which filled the air, can have 
any realization of the great numbers. In order to get some idea of the numbers, 
counts were made. In damp places or along the banks of streams, where the but- 
terflies had gathered to drink, as many as 150 individuals were counted in one 
square foot. Often the ground would be blackened by them for many square yards 
(see fig. 70) . 
Fig. 69. PUPAE AND ADULTS OF Eugonia californica. in one of The pupae, 
THE INSECT HAS BEEN DESTROYED BY SOME BIRD; IN THE OTHER BY SOME 
PARASITE. THE LATERAL VIEW OF AN ADULT SHOWS THE DARK UNDER SUR- 
FACE OF THE WING, AND THE DORSAL VIEW, THE COLOR PATTERN OF THE 
UPPER SURFACE. 
In order to estimate the numbers flying, counts were made of the individuals 
passing between two fir trees about twenty feet high and standing about thirty feet 
apart. The counts for ten successive minutes between 4:40 and 4:50 p. m. on 
August 20, were as follows: 
1st minute 
.105 
6tli minute 
100 
2nd “ 
119 
7th “ 
96 
3rd “ 
130 
8th “ 
102 
4th “ 
102 
9th “ 
83 
5th “ 
134 
10th “ 
.112 
Average per minute 108 
