LEPIDOPTERA. 303 



seems designed to render their footing more secure, and leaves a 

 slimy track wherever the insects go. Their cocoons are very 

 small, almost round, tough, and parchment-like, and are fastened 

 to the twigs of the plants on which the insects live. The moths 

 of some, if not of all, of the Limacodcs make their escape by 

 pushing off one end of the cocoon, which separates like a little 

 circular lid. 



The most common of these slug-caterpillars, in Massachusetts, 

 live on walnut-trees. They come to their full size in September 

 and October, and then measure five eighths of an inch in length, 

 and rather more than three eighths across the middle. The body 

 is thick, and its outline nearly diamond-shaped ; the back is a lit- 

 tle hollowed, and the middle of each side rises to an obtuse angle ; 

 it is of a green color, with the elevated edges brown. The boat- 

 like form of this caterpillar induced me to name it Limacodes 

 Scapha, the skiff Limacodes, in my Catalogue of the " Insects 

 of Massachusetts." My specimens generally died after they had 

 made their cocoons, and consequently the moth is unknown 

 to me. 



The moth of a Limacodes, called Cippus * by Sir J. E. 

 Smith, is sometimes found in Massachusetts, from the middle of 

 July till the tenth of August. It is of a reddish brown color ; on 

 each of the fore-wings there is a small dark brown dot near the 

 middle, and a broad wavy green band beginning at the base, and 

 bending round till it touches the front margin near the tip ; behind 

 a deep notch of this band, near the base of the wing, there is a 

 triangular tawny spot, and another smaller one near the tip. The 

 green band is sometimes broken into three triangular green spots, 

 the middle one of which is wanting in some specimens. One half of 

 the stalk of the antennas of the male is doubly feathered beneath ; 

 the remainder to the tip is bare. The antennas of the female are 

 thread-like and not fringed. The wings expand from one inch 

 to one inch and one eighth. The caterpillar figured by Mr. 



* Probably not the true Cippus of Fabricius, which is found in Surinam. There 

 is a figure of our species in Guerin's " Iconographie du Regne Animal," where 

 it is named Limacodes Delphinli, but for what reason I know not, for it does not 

 live on the Delphinium or larkspur. 



