518 



MERISTIC VARIATION. 



[part I. 



joint apparently representing the normal 4th, 5th, and 6th joints not segmented from 

 each other. [As this supernumerary part is in itself symmetrical it probably con- 

 tains within itself parts of a pair of clubs compounded in Position P. Cp. No. 

 795.] Jatne, H. F., Trans. Amer. Ent. Soc, 1880, vin. p. 158, PI. iv. fig. 8. 

 798. Polyphylla decemlineata (Lamellicorn). A specimen in which the right 

 antenna bears a partially double supernumerary branch in addition to the normal 

 antenna. This additional structure articulates with the second joint of the antenna 

 by means of a single large joint. This joint carries a double club consisting of two 

 sets of lamella?, seven being in each set. The two sets of lamellae are united at 

 their bases at an angle of forty-five degrees. The plane of the normal club is per- 

 pendicular to that of the abnormal ones. The normal club itself is Ath shorter than 

 that of the other side. [The details of the structure of this specimen are difficult 

 to follow and the reader is referred for further particulars to the description and 

 figures given in the original.] Jayne, H. F., Trans. Amer. Ent. Soc, 1880, vin. 

 p. 158, figs. 



(b) The extra parts arising from the normal at separate points. 



*799. Odontolabis stevensii % (Lucanidse). As the repetition in 

 this specimen is almost complete and the relations of the parts 

 fairly clear though in some respects peculiar, a detailed account 

 will be useful. 



The body, legs, &c. are normal, save that the back of the 



head and thorax have been crushed by some accident. The 



antenna? are both abnormal in the way shewn in Fig. 176. The 



•condition will be better understood if the normal antenna is first 



described. 



Fig. 176. Odontolabis stevensii, No. 799. The liead seen from below, and 

 enlarged views of the two antennae. 11, right. L, left. There is some doubt as 

 to which of the branches is the normal and which the supernumeraries. See 

 description in text. 



The normal antenna of Odontolabis is much like that of its 

 ally Lucanus cervus, the Stag-beetle. It is made up of 10 joints 

 composing three parts differentiated from each other. 



The first, or " scape, " is a single joint as long as the rest 

 of the antenna. It widens a little from its central end or base 

 towards the apex, and is slightly flattened from above downwards. 

 The second part, or " funiculus," has six simple joints. The last 

 three joints form the club. They are flattened from above down- 

 wards and lie in a horizontal plane. The anterior (" inner ") 

 border of each of these three joints is produced into flat ex- 

 pansions, covered with sensory pores, which together form a series 

 of serrations along the anterior border. When in its natural 



