160 
Psyche 
[December 
From this curve and data I conclude that there is but one 
brood a year. The adult beetles emerge during the first few days 
in August, remain quiet and inactive until forced by closing 
waters to go into the mud for the winter. The survivors, few in 
number, emerge in April and, after breeding, soon begin to die 
out and disappear. 
From observations made in a large concrete tank it is evident 
that there is a high mortality during the winter. The above 
statement is further shown to be probable by the death just 
after copulating on May 9, 1925, of the two surviving members of 
a colony which had been kept in a tank in a greenhouse during 
the winter. 
When first brought from the pond the beetles are greatly 
disturbed and try to get out of the dish by swimming and later 
attempt to climb the sides of the dish. At times they rustle their 
wing covers thus producing a buzz. They become accustomed to 
captivity after a while and finally are not alarmed even by quick 
movements of the hands in their close vicinity. At this stage 
they can be induced to feed from the fingers. I found few things 
they would not attempt to eat as anything that floated was 
eagerly seized and examined. Live mealy bugs, cracker crumbs, 
bits of salmon and sardines, bread crumbs, apple parings, meat 
and chocolate were all sampled besides many other materials. 
The only requirement seemed that of ability to float. The pre- 
pared fish food known as “Ant Eggs” composed mainly of ant 
pupae made a good food and a ground meat scrap containing no 
bone, put up by the Quaker Oats Company for poultry feed, was 
also successful. As long as this food remained on the surface the 
insects would rush about grabbing piece after piece. Sometimes 
two would snatch the same piece or one would attempt to take a 
portion from another. At such times they would dive and tear 
about under water until one lost its hold. 
The front legs are always used to hold and turn the food 
about. Sometimes the beetles would attach themseleves to my 
hand as I dipped it into the water. On such occasions the first 
was sure to be followed by others all pushing and striving to get 
at the particular place its neighbor occupied. They never were 
able to pierce the skin, although their attemps produced a tern- 
