5 1 4 MERISTIC VARIATION. [part i. 



(1) Clear cases of Supernumerary Antennce in Secondary 



Symmetry. 



(a) The extra ixirts arising together. 



f 788. Phyllopertha horticola (Lamellicorn) : specimen in which 

 the right antenna bears a supernumerary pair of clubs. This 

 specimen may conveniently be described in detail as it furnishes 

 a good example of the mode in which repetition of the antenna^ 

 occurs in the Lamellicorns. The left antenna is normal and 

 possesses nine joints (Fig. 173, L). The first is a large pear- 

 shaped joint, articulating with the head by its narrow end. The 



L R 



Fig. 173. Phyllopertha horticola, No. 788. L, the normal left antenna. E, 

 the normal right antenna. /, r, extra left and right clubs. 



second joint is also a pear-shaped joint, of about half the size 

 of the first. The third, fourth and fifth joints are elongated and 

 cylindrical. The sixth is short and wide. The seventh, eighth 

 and ninth are each expanded into a lamella. These three la- 

 mellae are generally kept firmly closed together and form the 

 sensory organ, or " club." In Melolontha (v. infra) and several 

 other genera of Lamellicorns, there are ten joints, of which seven 

 are developed as lamellae, forming the club. 



In the right antenna (Fig. 173, It), which bears the extra 

 pair of clubs, the basal joint is rather thick. The second joint 

 is longer than it normally is, and curves slightly backwards and 

 downwards. At its apex it bears the rest of the normal antenna, 

 which is in all respects well formed. In addition to the normal 

 antenna, the second joint upon its anterior surface gives attach- 

 ment to a large joint which is imperfectly constricted into two 

 parts in a vertical plane at right angles to the general direc- 

 tion of the normal antenna. Each of these half-joints bears a 

 structure containing in itself all the parts proper to an antenna 

 peripherally to the third joint, the clubs being well-formed and 

 normal. In absolute size they are equal, but are a little smaller 

 than the normal antenna. 



