1914] Life History of Lady Beetles. 
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observed in coition and the female laid a considerable number 
of eggs. A male of 9-notata was introduced into a cage of 
monticola which had been laying infertile eggs and though he 
mated readily no fertile eggs were produced. One female 
monticola was taken in coition with a male 5-notata. The eggs 
were fertile and produced all monticola, but this female may have 
been previously fertilized by another male so there is no evi- 
dence that the 5-notata male had any effect. 
There is a possibility of the males being weaker than the 
females and so being killed in the struggle for existence before 
they matured in the breeding cage, since about 50 per cent. 
were, as a rule, lost when a number were reared together. 
All the larvae from several batches were reared in individual 
cages. In this way 90 percent were brought to maturity and 
in the adult state all were put together in the same cage, but 
they always died down to the usual 50 percent before there 
was time for sexual development to be really completed, so that 
there is a probability in these cases of the males having been 
lost because of having a more delicate constitution than the 
females. This would also account for their scarcity out of 
doors. 
Two batches were reared in individual cages, maturing 17 
beetles from 18 larvae and 12 beetles from 23 larvae respectively. 
These beetles were not put together but were dissected by Mr. 
L. C. Bragg as soon as mature, the first lot proving to be 7 
male and 9 female and the second lot 9 male and 3 female. 
This latter case seems evidence against the possibility of the 
males being weaker than the females, as in this batch little 
over 50 percent matured and 75 percent were males. The 
only explanation remaining seems to be a sexual non-activity 
for some reason. 
A good share of the females captured proved to be infertile, 
when, however, a female is once fertilized it seems to suffice for 
the season. Females captured May 15, 1908, laid fertile eggs 
until August 18, 1908, a period of over three months, after which 
they very soon died. 
In spite of this seemingly weak point in its life history, this 
beetle seems to rank quite high as an eneniy of plant lice. 
