OF LEl'IDOrXEROUS I.VSECTS. 27 



This also varies according to the species : sometimes it increases gradu- 

 ally over the anterior third of the antennae; at others it is scarcely per- 

 ceptible ; sometimes it is formed by a sudden outjutting, either conical 

 and truncated, or laterally compressed and flattened ; sometimes hol- 

 lovved out spoon-shape, and sometimes terminated by a little point bent 

 back like a hook. In all the other Lepidoptera, which in opposition to 

 the former, have received the name of Hcieroccrata,* the antennae are 

 no longer found club-shaped, except in the tribe of the Castniae, which 

 in this respect slightly recall the preceding. They are either prismatic, 

 as in most of the Sphingidae; or linear as in the Sesiae : like a ram's 

 horn, as in the Zi/gaenae ; or simply bent outwardly like a bow, as in 

 the Aegoceridae. hi a great variety of genera they are filiform and at- 

 tenuated at their extremity; in others, mostly those which form a part 

 of the Bomhyx of the older authors, they are pectinated, that is, upon 

 each side they present a row of small teeth which have been compared 

 to those of a comb. When these teeth are long, and resemble the beard 

 of a feather, the attennae have been called plumaceous or feathered ; 

 those of many Geometrae give an example of this arrangement. 



The palpi are four in number, two maxillary, and two labial : but, 

 except in some races of Heterocerata, the former are always very dimin- 

 utive, and visible only by the aid of a very strong magnifier; they Iiave 

 most generally the form of a small tubercle, and are situated at the base 

 of the spiritrompe. The second, on the contrary, are generally very 

 distinct and erect, cylindrical or conical, covered v>ilh scales or with 

 very fine hair, formed by three articulations, of which the last, generally 

 very small, and almost obliterated in most of the Rhopaloccrata, is some- 

 times very long in the Heterocerata, forming there an acicular point 

 more or less prominent. The palpi are generally contiguous or conni- 

 vent ; but at other times they are considerably separated, with some 

 space between them. Some genera have them very scaly, others simply 

 bristled with rayed hairs, or the hair more or less soft. Generally they 

 are erect and gathered towards the front; but sometimes they are quite 

 straight and parallel to the axis of the body, as in the Libyiheac. Those 

 of the Emesis, another genus of Rhopalocerata, are small and so short 

 as scarcely to go beyond the base of the horn, so that at the first view 

 they would scarcely appear to exist in that genus. 



The spiritrompe is composed of two threads more or less long, 

 horny, concave upon their internal surfaces, with their edges fitting into 

 each other : when a transverse section is made we see that it is compo- 

 sed of three narrow canals, of which the intermediate one, according 



* £r£fo;o{ — variable ; jcf^« j = horn ; antennae of various forms. 



