  We study the discrete-time dynamical systems of a model of wild mosquito
population with distinct birth (denoted by $\beta$) and death (denoted by
$\mu$) rates. The case $\mu=\beta$ was considered in our previous work. In this
paper we prove that for $\beta<\mu$ the mosquito population will die and for
$\beta>\mu$ the population will survive, namely, the number of the larvaes goes
to infinite and the number of adults has finite limit ${\alpha\over \mu}$,
where $\alpha>0$ is the maximum emergence rete.
