The account given of the nesting habits of the above Andrena of our lawns, etc., is more or less true of nearly all the solitary bees. Their methods vary, some burrow in the ground, some in old wood, some in snail shells, some in bramble stems or straws or the hollow stems of various plants, some in holes or crevices in walls, etc., and their methods of building their cells vary exceedingly: all of these are of great interest and some display an ingenuity which is quite surprising. Of these special nesting habits some of the most striking will be mentioned later on.
Before leaving these general remarks on the
solitary bees the habits of two genera must be specially noticed, as they differ in an essential point from those of the others. These are known to entomologists under the names of Halictus and Sphecodes.
In most species of these the males and females of the new brood are not hatched out till after midsummer, and no work is done for the provisioning of new burrows that autumn; but the female, after having undertaken the duties of maternity, hibernates, i.e. goes back into a burrow and lives there till the next spring, the males dying off before the winter. In the spring the ♀ wakes up and does the necessary work for the future brood just as any ordinary spring bee would—but there are no attendant males—the duties of that sex having been performed in the autumn. The larvæ contained in these burrows hatch out after midsummer and therefore never spend a winter in the ground. In this respect they resemble the social bees and wasps, about which more hereafter; in the meanwhile a few words must be said about the cuckoos or inquilines, which are perhaps the most interesting creatures of all.
THE CUCKOO BEES
These cuckoos live at the expense of their hosts. The mother of the industrial brood makes her cell and provisions it, and lays her egg. The cuckoo bee manages to enter also and lay her egg in the same cell, the usual result being that the cuckoo devours most of the food instead of the rightful offspring, which gradually gets starved and dies, the cuckoo appearing in its place; but there have been cases, how frequent they are is difficult to say, in which both offsprings have emerged.
The whole problem of the relationships between host and cuckoo is most interesting. In some cases the cuckoos are so like their hosts that it is difficult to tell one from the other, in others they are so unlike that it is difficult to trace any resemblance between them. There are a great number of different kinds of cuckoos, and most of them select a special host to associate