THE FORK-TAIL MOTH. 423 



an inch and a half in length, without including the terminal 

 fork. Caterpillars of this kind are called Centra, horned- 

 tail, by some, and Dicranura, forked-tail, by other natural- 

 ists. Early in August the one above described makes a 

 tough cocoon of bits of wood and bark glued together with 

 a sticky matter, and fastened to the side of a branch, the 

 lower side being flat and the upper convex. The last trans- 

 formation occurs about the middle of June, when, after the 

 end of the cocoon has been softened by a liquid thrown out 

 by the insect within, the moth forces its way through. This 

 insect has been figured in Mr. Abbot's work,* where it is 

 called furcula, a name, however, which belongs to an Euro- 

 pean insect. It is also represented in Guerin's "Icono- 

 graphie," and in Griffith's translation of Cuvier's " Animal 

 Kingdom " ; and I have adopted the specific name given to 

 it by Dr. Boisduval in these works. Cerura borealis, the 

 northern Cerura, or fork-tail moth, like others of the genus, 

 has the antennas feathered in both sexes, but narrow, and 

 tapering and bent upwards at the point ; the legs, especially 

 the first pair, which are stretched out before the body when 

 at rest, are, like those of our native Limacodes, very hairy ; 

 and the wings are thin and almost transparent. The ground- 

 color of our moth is a dirty white ; the fore wings are 

 crossed by two broad blackish bands, the outer one of which 

 is traversed and interrupted by an irregular wavy whitish 

 line ; the hinder margins of all the wings are dotted with 

 black, and there are several black dots at the base, and a 

 single one near the middle of the fore wings ; the top of 

 the thorax is blackish, and the collar is edged with black. 

 In some individuals the dusky bands of the fore wings are 

 edged or dotted with tawny yellow ; in others, these wings 

 are dusky, and the bands are indistinct. They expand from 

 one inch and three eighths to one inch and three quarters. 



The following insects, for the sake of convenience, may 

 be included in the old genus Nbtodonta. The first of them 



* Insects of Georgia, p. 141, pi. 71. 



