body almost always elevated and curved in the form of the letter S. Additional distinctive characters might be mentioned, such as the form of the eyes, which are pretty large in pseudo-caterpillars, and placed one on each side of the head, while in true caterpillars they are small almost invisible points disposed in a circle; but those already referred to will suffice to distinguish the two tribes.
The body of pseudo-caterpillars is generally composed of twelve segments, but the incisures are indistinctly defined, and liable to be confounded with the transverse wrinkles which thickly cover the whole surface. Many of them are marked with bright and varied colours, but the majority are of one colour. In this respect they often undergo a remarkable change after they have cast their last skin, the colour becoming entirely unlike what it was before, so that it is impossible to recognise the same individual. This change, indeed, extends even farther than to colour, for such kinds as are furnished with tubercles or spines in their earlier stage, lose them at their last moult and become smooth; that of the gooseberry species, for example, loses the black tubercles which made the surface appear as if shagreened. Like the flies they produce, these larvæ are sluggish and inactive, seldom moving from the place where they have fixed themselves, unless when requiring an additional supply of food. When not engaged in feeding, or when apprehensive of danger, they roll themselves into a circle, sometimes with the tail elevated in the centre. The greater
