226 THE entomologist's hecord. 



ell/.). Kolbe*-' says: " In the Diptera, Lepidoptera and Trichoptera, 

 whose mouth-parts are stunted, absent or transformed into sucking 

 organs, the antennae are brought very near each other, while in biting 

 insects, they are usually separate from each other." The antenna? 

 of Microptenj.v, which has retained its mouth parts, are relatively 

 far apart, and hence appear to bear out this generalisation. 



The proximal segment of the antenna is called the scape (fig. 7, 

 ■see.). Next to it is the pedicel (fig. l,p.), the two together being 

 sometimes known as the base. The remaining segments make up the 

 clavola (fig. 7, cL). Among moths, the latter is often pectinate, when 

 that part of the antenna made up of the bodies of the segment is 

 called the shaft, and the projections, the pectinations. Among the 

 Papilionides, Hesperides and, to a less extent, the Zyg.enides, the 

 clavola is divided into the funicle or stalk, and a clavate portion or 

 club. The scape is somewhat rounded at the end, and is inserted into 

 a little cup-like depression in the head, so that a very serviceable 

 ball-and-socket joint is produced in some species. This explains 

 the freedom of movement often observed. 



Although the scape is abundantly supplied with strong, striated 

 muscles, the other segments appear to be devoid of muscular tissue. 

 The chitinous parts of all the segments are held together by a tough 

 flexible membrane, and it is due to the elasticity of the latter that, 

 when the clavola is bent by external force, it is able to resume its 

 original shape. The clavola itself consists of (1) The chitinous parts 

 of the segments held together as just described. (2) A layer of dermal 

 and nerve cells, with numerous interlacing nerve-fibres just within the 

 chitinous coat. (3) A large tracheal trunk, supplying branches to the 

 segments. This lies along the ventral part of the shaft. (4) A pair of 

 large nerves, which come from the frontal ganglion, and send out 

 branches to the various organs of sense located in the antennjv. These 

 nerves are just by the side (dorsad) of the trachea. (5) The remainder 

 of the substance in the antenna is blood, which bathes the tissues, and 

 nourishes them. 



The chitinous covering of the antennae is supposed to be formed 

 by secretion from the dermal cells directly underlying it. Its surface 

 is frequently marked into roughly hexagonal areas (PI. II., figs. 8-9), 

 which, in Xotolojihiis {On/i/ia), are limited by thin continuous ridges of 

 chitin. Frequently the surface is broken up into fine points and 

 ridges, and the outlines of the plates are thus obscured. 



The many structures found on the antenna^ of Lepidoptera are 

 regarded by Bodine as modifications of a simple hair. "Each has 

 its origin in a hypodermal cell, and is, therefore, connected with the 

 interior through a pore-canal. The simplest form is that of a simple 

 protective hair. When the hair is flattened out, we have the typical 

 scale, which also rises from a hypodermal cell. The antennal scales 

 are inserted differently from those found on the wingmembrane." " The 

 pedicel or stalk is set in a goblet-shaped cell, lying in the chitin, with 

 its long axis nearly perpendicular to the surface, but pointing 

 slightly distad. The bottom of the cup is at the end of a pore-canal, 

 but there is no evident vital connection with the interior." In the 

 scales which are inserted in the wing membrane, " the cups have their 

 long axes nearly parallel with the surface, and they seem rather to be 

 built up upon the membrane, than to be hollowed out of it." 



* Einsfiihrung in die Kenntniss der Insekten, von H. J. Kolbe, Berlin, 1893. 



