RKLI.CUX;: SCLERITES OF THE HEAD. 55 



verse sclerite, fixed, and usually plainly distinguished from the clypeus 

 (see /a in fig. ii, Plate II). It bears uniformly, as far as I have 

 observed, two tapering, forward-projecting points, rising from the 

 ends of the transverse portion of the sclerite (see // in fig. ii, Plate 

 II). These points bear on their inner margins a row of short, bristly 

 hairs, which are usually of light-brown color. These colored hairs, 

 indeed, will often lead to the detection of the projections which other- 

 wise might remain unnoticed. These hair-bearing labral projections 

 are the points designated as mandibles by *Burgess in his memoir on 

 archippiis. Probably the first description of these processes as man- 

 dibles is that by Savigny (1816) in the following words: " Les man- 

 dibules sent d'une exiguete proportionee a celle de la levre superieure. 

 Dans la plupart des especes.elles paraissent a la loupe beaucoup moins 

 grandes que les ecailles qui couvrent le chaperon; elles sont appuyees 

 sur les deux cotes de la trompe, et trop 6cart6es pour pouvoir se 

 toucher par leur sommet. Leur mouvement est assez obscur et dans 

 certains genres, comme dans les SpJiinx elles paraissent plutot soudees 

 au chaperon qu' articulees; d'autrefois elles font corps avec le base de 

 la levre superieure; elles sont d'ailleurs cornees, tres lisses dessus et 

 dessous, vides au dedans, tantot applaties, tantot renflees, plus ou 

 moins coniques; divergentes, paralleles ou convergentes; pointues ou 

 obtuses, suivant les genres, mais dans tons bordees de cils tres-epais 

 sur leur tranchant interieur. " I think there is no doubt of the contin- 

 uity of the mandibles with the labral sclerite. When present in 

 lepidoptera they articulate or fuse with the genae (so far as I 

 have observed), and the labral projections, which I suggest may be 

 known as the fpilifers, are to be found in a specimen along with 

 mandibles, but distinct from them. This is plainly shown in Proto- 

 parce Carolina, where the rather conspicuous mandibles plainly arise 

 from the genae, showing a faint suture of articulation, and being 

 strongly chitinized at the tooth-like tips. The pilifers are 

 large, and are manifestly distinct| from the mandibles (see md and 

 // in fig. 2, Plate II). In Hemaris tJiysbe the suture between 

 the mandibles and gena is obsolete, and the mandible appears 

 as a strongly-chitinized, brown-pointed projection of the gena. The 

 pilifers, evidently processes of the labral sclerite, are present (see ind 



*Bvirgess, Edw. Loc. cit. 



tWith the scanty means of referenC3 at my command I may be unaware of a previously 

 suggested name for these processes. 



iOti this point Newport says in his article •• Insecta " in Todd's Cyclopedia of Anatomy 

 and Phvsiologv 1 1S36-39), discussing the mouth-parts of Sphinx ligustri; ■■ On each side of 

 the labrum are the rudiments of the mandibles. They are two minute triangular plates, 

 attached in part to the labrum and margin of the clypeus, to which as Savigny has re- 

 mari^cd tht-v appear to be soldered. They are applied to the base of the maxilla, and in 

 Sjihuix appear each to be formed of two parts, and are covered along their margin with stiff 

 hairs. ■■ It is the outer one of the " two parts " which I take to be the mandibular remnant 

 and the inner one, the pilifer. 



