476 LEPIDOPTEEA. 



Some of them have sixteen legs, others have only fourteen. 

 The latter creep very much like the span-worms, but are 

 more active and quick in their motions. Most of them 

 live exposed upon or under the leaves of plants, and, when 

 they come to their full growth, they enclose themselves 

 in cocoons formed of folded leaves thinly lined with silk, 

 in which they undergo their transformations. Some kinds 

 (Hydrocampa and Petrophila) live in the water upon aquatic 

 plants, and secure themselves in cylindrical leafy cases, fitted 

 to cover the whole of the body except the head and six fore 

 legs, and made air-tight. These cases prevent the water 

 from getting into the lateral breathing-holes of the cater- 

 pillars, and contain a sufficient quantity of air for them to 

 breathe ; and, with them, they can easily move about under 

 the surface, upon the plants which serve them for food. 

 Some of the aquatic kinds do not make these air-tight cases, 

 for they do not need them, as they breathe through fringed 

 gills, placed along the sides of their bodies. Thus we see 

 that even aquatic plants are inhabited by peculiar tribes of 

 insects, which keep in check their redundant vegetation, and 

 which are fitted, by extraordinary and curious contrivances, 

 for the element wherein they are appointed to live. These 

 aquatic insects stand on the limits of the order, and con- 

 nect the Lepidoptera with the Neuroptera^ by means of the 

 May-flies (PJiryganeadce) belonging to the latter order. 



Those caterpillars of the Pyralides that have only fourteen 

 legs may be called Herminians (HERMINIAD^E), after the 

 principal genus in the group. The hop-vine is often infested 

 by great numbers of these caterpillars. They eat large holes 

 in the leaves, and thereby sometimes greatly injure the plant. 

 Caterpillars of this kind have also been observed on the 

 hop in Europe, from whence ours may have been intro- 

 duced; but until specimens from Europe and this country 

 are compared together, in all their states, it will be well 

 to consider the latter as distinct. Our hop-vine caterpillars 

 are false-loopers, bending up the back a little when they 



