272 Arthropoda. 



workers possess "baskets"; ttey do not build cells, but tbe eggs ai-e laid each 

 upon a little lump of bee-bread and honey, into which the young larva gi-adxially 

 eats, increasing in size by the ingestion of new material ; before pupating, it 

 spins a glossy ovate covering ; this cocoon which has been wrongly regarded as a 

 cell, may sometimes be used for the storage of food, after the Bumble-bee has 

 ■crawled out of it. The females of many Solitary-bees form small cavities 

 in the earth or in wood, or trae cells of sand, loam, or pieces of leaves. Pollen 

 or honey is stored in these cells, and one egg is laid in each, and then it is 

 closed; the larvse feed on the stores, the female taking no further trouble 

 about them. The females, as well as the workers of some of the solitary 

 Bees, possess baskets ; in others, the pollen is collected on the "thick hairy 

 ■covering of the hind legs, or on the hairy ventral surface of the abdomen. 

 Not a few of the soHtary forms are parasitic (Cuokoo-bees), laying theii' eggs 

 in the stores of other Bees, so that their larvae may live at the expense of these 

 supplies. 



Order 6. Lepidoptera. 



THe Lepidoptera are Holometabolous Insects, with four 

 ■equally developed wings, and with sucking mouth 

 parts. The whole animal is well covered with hairs. The head is 

 freely movable ; the multiarticulate antennae are filiform or bristle- 

 like, clavate, or pectinate, etc. For the structure of the mouth 

 parts, see p. 233. The three thoracic segments are intimately 

 ■connected, the prothorax small, the mesothorax large. The wings 

 are large, covered with minute coloured imbricating scales (flattened 

 setae), or "dust," which usually form a complete covering over 

 the veins and the rest of the surface ; the fore wings are longer, 

 but generally also narrower than the hind ones. The latter very 

 ■often bear on the anterior margins, close to the point of origin, a 

 strong bristle, or group of stiif bristles, {retinaculum), which fits 

 into a small ring on the ventral surface of the fore wing; by this 

 means the two vnngs of the same side are coupled. At the base 

 of the fore wing there is a specially developed scale, just as in the 

 Hymenoptera, but often still larger than in this group. The legs 

 :are feeble, with large coxae and pentamerous tarsi, the basal 

 joint being much longer than the rest (c/". the Hymenoptera). 

 There is no deep constriction between the thorax and abdomen, 

 and the latter is therefore "sessile." The larvee, "caterpillars," 

 are of a very distinct type. They are cylindrical, with a long 

 abdomen, bearing prologs ; they are almost exclusively phytophagous, 

 and for the most part lead a free existence upon leaves, and in 

 connection with this, and in contradistinction to" most other insect 

 larvae, they are often brightly coloured : the exoskeleton is fairly soft, 

 with the exception of the firmly chitinised head and prothorax. 

 'There are five or six ocelli on each side of the head, a pair of short, 

 three-jointed antennee, and the usual biting mouth-parts. The thorax 

 is provided with three pairs of short legs, each with a single claw. 



