The caterpillar, when full fed, makes a cocoon with silk and the chips of wood that it has bitten off; and in this undergoes its metamorphoses. It is fully grown in April, and the moth flies from the end of May to the end of July. There is another 'Hornet Clearwing,' the larva of which feeds on the stems of osiers. It may be distinguished from the species just described by a yellow 'collar' between the head and thorax, both of which are blackish. _The Currant Clearwing_ (_Sesia Tipuliformis_) This is by far the commonest of all the Clearwings, and only too well known to those who grow currants. Examine the shoots of _Ribes rubrum_ (red currant) and _R. nigrum_ (black currant), especially those that present a withered or half-withered appearance, and you will almost certainly meet with signs of the presence of this intruder. Little wriggling larvae occupy the pithless stems throughout the winter and spring. These are full grown in April, and in June the pretty little moth emerges through a hole in the side of a shoot, leaving the empty pupa case within its former home. [Illustration: FIG. 104.--THE CURRANT CLEARWING.] The fore wings of this moth have black margins, and a black transverse bar beyond the middle. The body is black, with three pale yellow belts, and black tufts of hair at the tip. Family--ZYGAENIDAE The remaining family of the _Sphinges_--the _Zygaenidae_--includes seven British species, three of which are known popularly as the Foresters and the others as the Burnets. Their antennae are thickest beyond the middle, but do not terminate in a hook. Their wings are narrow and completely covered with scales. These moths are very sluggish creatures, spending the greater part of their time at rest on the stems of low-growing plants. When they do fly, their flight is short and heavy, and their pretty wings glisten in the sunshine (for they are lovers of the sun), giving them the appearance of bees rather than of moths. On account of this natural sluggishness, they are exceedingly local, for they never move far from the spots where their food plants abound, and where they had previously spent the earlier stages of their existence. Thus we often come across a very limited piece of ground actually alive with them, and outside which not a single specimen is to be seen. The larvae, too, are sluggish creatures, with soft and plump cylindrical bodies and no horns. I will briefly describe three members of this family. _The Forester_ (_Ino Statices_) The fore wings of this species are semi-transparent, and of a beautiful glossy green. The hind wings also are semi-transparent, but of a dull smoky tint. The thorax and abdomen are both of a brilliant metallic green colour. The tips of the antennae are blunt, and the male may be distinguished from his mate by these organs being slightly fringed or ciliated. [Illustration: FIG. 105.--THE FORESTER.]