Fossorial Hymenoptera are distinguished from other Aculeates at present only by negative characters, _i.e._ they are Aculeates, but are not ants, bees or wasps. According to their habits they fall into four, by no means sharply distinguished, groups—(1) those that form no special receptacles for their young, but are either of parasitic or sub-parasitic habits, or take advantage of the abodes of other Insects, holes, etc.; (2) constructors of cells of clay formed into pottery by the saliva of the Insect, and by drying; (3) excavators of burrows in the ground; (4) makers of tunnels in wood or stems of plants. Several species make use of both of the last two methods. The habits are carnivorous; the structures formed are not for the benefit of the makers, but are constructed and stored with food for the next generation. Their remarkable habits attracted some attention even 2000 years or more ago, and were to some extent observed by Aristotle. The great variety in the habits of the species, the extreme industry, skill, and self-denial they display in carrying out their voluntary labours, render them one of the most instructive groups of the animal kingdom. There are no social or gregarious {91}forms, they are true individualists, and their lives and instincts offer many subjects for reflection. Unlike the social Insects they can learn nothing whatever from either example or precept. The skill of each individual is prompted by no imitation. The life is short, the later stages of the individual life are totally different from the earlier: the individuals of one generation only in rare cases see even the commencement of the life of the next; the progeny, for the benefit of which they labour with unsurpassable skill and industry, being unknown to them. Were such a solicitude displayed by ourselves we should connect it with a high sense of duty, and poets and moralists would vie in its laudation. But having dubbed ourselves the higher animals, we ascribe the eagerness of the solitary wasp to impulse or instinct, and we exterminate their numerous species from the face of the earth for ever, without even seeking to make a prior acquaintance with them. Meanwhile our economists and moralists devote their volumes to admiration of the progress of the civilisation that effects this destruction and tolerates this negligence. [Illustration: Fig. 37.—_Sceliphron nigripes_ ♀ (Sub-Fam. Sphegides). Amazons. × 3/2.]