chap, xx.] EXTRA ANTENNAE ARISING TOGETHER. 517 



The morphological nature of this supernumerary organ may 

 be determined thus. The upturned edges of the folds bear 

 hairs as shewn in the figure A; since in the normal antenna 

 the dorsal edges of the lamellae alone bear hairs, these edges 

 are in this case dorsal morphologically as well as by position. 



Since the outermost lamella (marked 4) is articulated into 

 the third joint of the funiculus, it is therefore the 4th joint, or 

 proximal lamella, and the remaining lamellae are therefore 5th, 

 6th, 7th, 8th, 9th and 10th respectively. Next, the surface ////• 

 is structurally like that of the internal (sc. anterior) surface of 

 the proximal lamella of a normal club, and the surface ml is a 

 similar surface : but ml, being an internal surface, faces towards 

 the right and is therefore morphologically a left; while mr, being 

 an internal surface and facing towards the left, is a right ; hence 

 this club consists of two clubs compounded together by their 

 external or posterior borders, and the two are a right and a left, 

 the left being next the normal right club. 



Lastly, since the upper free edges of the lamella* are structur- 

 ally dorsal, it follows that their lower edges are structurally 

 ventral: but these lower edges do not exist as free edges, f'« >r 

 the lamellae are continuous upon their ventral aspect : therefore 

 the surfaces which are adjacent in the extra right and left clubs, 

 and by which they are compounded together, are partly ventral 

 surfaces. This is approximately Position DP of the Scheme. 



Left Antenna. Second joint thickened and presenting three 

 articulations as follows. 1. a peripheral articulation bearing the 

 normal club ; 2. a ventral articulation bearing a 4th joint and 

 club composed of 3 formless lamellae ; 3. a dorsal articulation 

 bearing a small cylindrical joint only. The shape and formation 

 of these extra parts is so indefinite that their morphology could 

 not be determined. 



For the loan of this specimen I am indebted to Dr L. v< »x 

 Heyden, who first described it in Deut ent. Zt. y 1881, XXV, p. 10"), 

 fig. 1. 



796. Rhizotrogus aequinoctialis (Lain.) : 4-th joint of right antenna 

 bears a supernumerary structure projecting forwards and lying in the 

 same horizontal plane as the normal club. This structure is lanceolate 

 in form and its outer surface is in texture similar to the external surfaces 

 of a normal club. On the ventral aspect it presents a simple ridge, but 

 on the dorsal side its outer coating is divided by a spindle-shaped slit 

 through which part of the internal structure protruded. The edges of 

 this opening and the protruding portion of the interior bear a few 

 hairs. There can be little doubt that this supernumerary body repre- 

 sents an imperfectly formed pair of cluhs, and that it is in fact a more 

 rudimentary condition of the parts found in No. 795. Specimen origi- 

 nally described and tigured by Mocquerys, Col. anorm., p. 1 •>,./?'#. 



797. Llchnanthe vulpina (Lam.) : right antenna bears in addition to normal club a 

 small spherical club made up of three joints, arising from posterior border of a l<>n^ 



