chap, xxii.] DOUBLE APPENDAGES : INSECTS. 



545 





wards, but its tibia curves backwards. The femora are so twisted 

 that I failed to determine the symmetry of these legs ; and while 

 it was clear that neither was a normal left it was equally doubtful 

 whether either was shaped as a right. Of all cases in Insects 

 this is one of the nearest to the condition of true duplicity. Hope 

 Collection, Oxford. 



846. 



847. 



845. Carabus intricatus : middle right femur is partially bifid, pre- 

 senting two apices in the same horizontal plane. The anterior apex 

 bears a tibia and tarsus of nearly normal form. The other apex bears 

 a tibia and tarsus of full length but much more slender than a normal 

 one. This leg was ill-formed. The tibia bore no spurs, and there 

 was no indication as to its symmetry, and nothing shewed that it was 

 a right or a left leg. It is stated in the original description that the two 

 legs could be separately moved and that both assisted in locomotion. 

 Originally described by Mocquerys, Col. anorm., p. 45, Jig. 



Melolontha vulgaris : right anterior leg divided to form two 

 legs. The femur dilates in peripheral third to form two apices, each 

 bearing a tibia. These two tibiae are at right angles to the femur and 

 are together in the same straight line, the one pointing forwards and 

 the other backwards, each tibia turning its ventral or flexor surface 

 towards the femur. The anterior tibia carries a tarsus of 4 joints 

 with claws, while the posterior tibia has a normal tarsus of five joints. 

 For a figure of this specimen and particulars concerning it I am in- 

 debted to Professor Alfred Giard. 



Leptura testacea (Longic): in tarsus 

 of left middle leg the 2nd joint presents two 

 apices (Fig. 204). The posterior bears normal 

 3rd and 4th (terminal) joints with a proper 

 pair of claws. The anterior apex bears a 

 narrow 3rd and 4th joint, the latter having 

 only a single median claw [cf. No. 848]. 

 Kraatz, Deut. ent. Zt., 1876, xx. p. 378, 

 fig. 14. 



848. Tetrops praeusta (Longic.) : right 

 anterior femur widened towards apex, which 

 presents two articulations in same horizontal 

 plane. Each of these bears a tibia. The post- 

 erior tibia and tarsus are complete in all 

 respects, but they flex downwards and back- 

 wards. The anterior tibia has a normally 

 4-jointed tarsus, but the apical joint bears 

 only one claw, and there is no sign of muti- 

 lation [cp. No. 847]. Were it not for the 

 closely similar case of Silis No. 764 there 

 would be no reason to doubt that this is 

 a true case of duplicity, but that example 

 shews how masked may be the doubleness of extra parts ; and though 

 I could not prove either of these legs to be double I feel no certainty 

 that one of them is not double. Specimen very kindly lent for descrip- 

 tion by Mr F. H. Waterhouse. 



r. 35 



Fig. 204. Leptura tes- 

 tacea, No. 847. Tarsus of 

 left middle leg from the 

 plantar surface. (The pro- 

 perty of Dr Kraatz.) 



