370 NATURAL HISTORY. 



may serve to give access to several cells. In the nearly allied genus Halictus (or Hylceus) this 

 habit of multiplying the cells seems to be general. In all, the cells terminate the tunnels, and when 

 stoi-ed with food and furnished with eggs the female closes the aperture of the burrow. As a general 

 rule the development of these burrowing Andrenictae takes place in the following fashion : The 

 larva, when hatched, feeds upon the supply of food left for it, undergoes its change to the pupa state, 

 and in this condition remains in its cell through the winter, to emerge at the same season of the 

 year at which the egg was laid ; but in some cases there appear to be two broods in the course of the 

 year ; and in Halictus and an allied genus (Sphecodes) it would seem that the insects escape from 

 the nests in the autumn, and the females, after impregnation, survive the winter in sheltered places, 

 and commence their nest-making operations in the spring, thus following the same course as the 

 Humble Bees. The species of Sphecodes are very unlike Bees in their general appearance, being 

 generally smooth black insects, with more or less of the abdomen red, and the females have no 

 apparatus for carrying pollen either on the legs or the abdomen. Other species of this group, 

 especially those of the genus Prosopis, have been observed to make their nests in bramble-sticks. 



The Andrenidse are particularly subject to the attacks of those peculiar parasites which infest 

 Bees, especially the coleopterous Stylopidse and Meloidse. 



FAMILY VESPID^:, OR WASPS. 



The Wasps, which, like the Bees, are both social and solitary in their mode of life, form the 

 second family of the aculeate Hymenoptera, called Vespidse, from the name of the genus (Vespa), 

 which includes the best known species. One of their most striking characters is to be found in the 

 fact that the fore wings, which, as in the Bees, have either t\vo or three submarginal (or cubital) 

 cells, are capable of being folded down the middle, so that the wings of each side of the body form a 

 straight band only about half the width of the fore wing. The first discoidal cell is very long, being 

 much produced towards the base of the wing. In their general structure they approach the Bees, but 

 are of a more slender form, and usually much less hairy. The posterior tibiae and tarsi are simple and 

 not dilated ; the sides of the prothorax are produced back as far as the root of the wings ; the 

 antennae are, as in the Bees, more or less kneed at the end of the long first joint ; the eyes are kidney- 

 shaped; the mandibles well developed and prominent ; and the maxillse and labium do. not, as in the 

 Bees, form a sort of proboscis. The labium is wide in front, and its palpi are either three or four- 

 jointed ; the maxillary palpi consist of six joints. Species of this family occur in nearly all parts of 

 the world, and about 1,000 of them are known. 



The social forms, which, in the beauty of their architecture rival, if they do not excel, the Hive 

 Bee, are distinguishable from the solitary ones by certain structural peculiarities ; the claws at the ends 

 of the tarsi are simple, and the mandibles are broad. These insects live in communities of various 

 sizes according to the species, consisting, as in the Bees, of three kinds of individuals, males, perfect 

 females, and workers. Their nests, which are among the most beautiful examples of insect architec- 

 ture, are found either in holes in the ground, or in hollow trees, and similarly sheltered situations, or 

 freely suspended from the twigs or branches of trees. The material of which they are composed is a 

 sort of rough paper or cardboard, composed of portions of plants, usually woody in their nature, 

 gnawed up by the insects and brought into the condition of a paste by means of their salivary 

 secretion, which is of so viscid a nature as to hold the particles of vegetable matter very solidly 

 together. In fact, the material of which the nests and cells are constructed often shows a marvellous 

 smoothness of surface ; the workmanship of the cells is always of great beauty. The cells are 

 hexagonal in form and placed side by side so as to form regular combs, but there is only a single row 

 of cells in each comb, and in most cases their apertures are turned downwards. The combs as they 

 increase in number are placed one above the other, and usually attached to each other by small 

 columns of the paper-like material of which the nest is composed. 



Although some of the nests may contain several thousand individuals, and a much larger number 

 of cells, each community (at any rate in temperate climates) originates from a single female Wasp, 

 which, having arrived at maturity and been impregnated in the preceding autumn, and passed the winter 

 in a state of torpor concealed in moss, or some other shelter, comes forth with the first mild days 

 of spring and lays the foundation of the nest. The proceedings of this foundress of the colony are so 



