60 Trans. Acad. Sct. of St. Louts 
all those in their natural environment also disappear at 
this period. Very soon after that date one may, by very 
careful watching, find the young nymphs frolicking about 
sink and pantry. Toward autumn they reach a fair size 
of nymphal development and become conspicuous enough 
to once more attract the attention of the housewife. If 
they are captured at this time and kept in confinement, 
they become adult in May or June. This, of course, leads 
one to believe that the life cycle normally covers about 
one year. There is much misapprehension as to the 
length of the life cycle. Ealand says: ‘‘ After the first 
year, moults take place annually.’’ 
Dates when nymphs transformed into adults.— 
Nymphs taken in August and September, 1915, and kept 
in large fish globes with plenty of food, transformed 
into adults (with one exception) the following May and 
June on tke following dates: 
Date Males Females Date Males Females 
May 8 1 = May 28 1 1 
12 1 1 29 2 1 
15: 10 3 June 1 2 3 
16 1 1 3 + 1 
17 i = 5 1 2 
18 1 i 6 1 1 
19 1 Se 7 1 = 
20 2 1 9 1 2 
21 ro 2 13 1 3 
22 4 = 15 1 ] 
23 3 1 16 ao 2 
24 1 1 July 29 2 1 
25 1 1 : oo —_ 
26 2 { Total____47 31 
27 1 1 oe 
