Doug, thanks for pointing out the confusion about the insect question. I did not know that the current printing of Silvey is different!

Here is the question:

An entomologist samples at random from a large pop. of a species. She records the sex of each insect and stops sampling after obtaining M > 1 males, by whichtime the total sample size is x. Find an MVUE of theta, the proportion of males in the pop.