506 



MEBJSTIC VARIATION. 



[part t. 



other. The present case therefore is very different from those hither- 

 to described, for in them the planes of reflexion were nearly or quite 

 parallel. Whether this difference in the Symmetry of the extra parts 

 may be connected with the departure of the normal tibia from its own 

 customary symmetry cannot be affirmed, but such a possibility should 

 be borne in mind. 



This specimen was kindly lent to me by Dr G. Kraatz, who first 

 described it in Deut. ent. Zt., 1877, xxi. p. 62, fig. 23. 



Dorsal 



t 3 Posterior 



A/2 I 



II 



Posterior 



Anterior 





Fig. 169. I. Ground-plan of tibial apex of Calathus grams, No. 776. 

 II. Similar ground-plan of the tibial apex of Calathus cisteloides, No. 777. 



In each case the spurs are conceived as projected upon one plane, t 1 , the 

 normal tarsus. A 1 , P 1 , its anterior and posterior spurs, t 2 , A 2 , P 2 , similar parts 

 of nearer extra tarsus, t 3 , A 9 , P s , similar parts of remoter extra tarsus. M 1 , 

 plane of reflexion between t 1 and t 2 . M 2 , plane of reflexion between i 2 and t 3 . 



Calathus cisteloides ^ (Carabidae): right anterior tibia bearing 

 a pair of supernumerary tarsi compounded together. In this case the 

 extra parts were anterior to the normal tarsus. The parts were 

 arranged as in the diagram, Fig. 169, II, which is a projection of the 

 tibial apex. The apex is produced anteriorly so as to form a wide 

 expansion which bears the common articulation for the double tarsus. 

 This produced portion is of course formed by the composition of parts 

 of a pair of tibiae. It is noticeable that the three tibial apices which 

 enter into the formation of the general apex are in one respect not 

 actually images of each other. For the angular distances between A 1 

 and P 1 , and between A 2 and P 2 , are exceedingly small, being far less than 

 in a normal tibia of the species, and in fact the grooves running from 

 each anterior spur to the corresponding posterior one are almost paral- 



