506 



.MKHISTIC VARIATION. 



[l-AHT I. 



other. Tin- pre-ent case then-fore is very different from those hither- 

 to described, t'"i- in tin-in the planes of reflexion were nearly or quite 

 |. n.-ill.-l. \\'ln-th.-i- tlii.-, ilitli-i-i-iice in the Symmetry of the extra parts 

 in.-iv In- i-oiinecied with tin- (li-jiarture of the normal tibia from its own 

 customary symmetry cannot be affirmed, but such a possibility should 

 In- bin-Hi 1 in mind. 



Thi- -periinen was kindly lent to me by Dr G-. KRAATZ, who tirst 

 descril)i-d it in />///. ,///. Zt., 1877, xxi. p. 62, tig. 23. 



I) or mil 



t 3 Posterior 

 M' I 



II 



Ponterior 



An If nor 



FIG. 16!). I. Ground-plan of tilrial apex of Calathus grams, No. 776. 

 II. Similar ground-plan of the tibial apex of dilutlm* cixti'loides, No. 777. 



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

 normal tarsus. .I 1 , I' 1 , its anterior and posterior spurs, t-, A-. P-, similar parts 

 of ni-aivr i-xtra tarsus. / :) , .! :; . !', similar parts of remoter extra tarsus. 3/ 1 , 

 plane of reflexion between t 1 and t-. .!/'-', plane of reflexion between t- and f :t . 



*777. Calathus cisteloides J; (Carabid;e): 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 

 liliial api'\. The apex is produced anteriorly so as to form a wide 

 i-xpansion whirh bi-ai-s the common articulation for the double tarsus. 

 This produced pm-timi is uf i-uiirse funned by the composition of parts 

 i it' a pair of tibia-. It is noticeable that the three tibial apices which 

 i-nti-r 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 1", and betwrni A' and 1'-', are exceedingly small, being far less than 



in a normal tibia of the species, and in fact the "moves runnin<* from 



i'ii 

 each .-interior spur to the corresponding posterior one are almost paral- 



