496 M ERISTIC VARIATION. [PART I. 



en -i-nce of tu-n channels on its concave surface. Position of origin is therefore D, 

 whili- tin- iui-liiiiitii.il i.l' tin- c.\tr:i pairs of claws to each other is about that required 



A. 



Fi.,. Hi::. <;,,l,',-it<i africana, No. 758. Apex of right middle tarsus. A, 

 anterior. P, posterior. I", ventral. (Specimen in Rouen Mus.) 



for the position DDA; fur the planes of the two pairs are not parallel but incline 

 to each ntlii-r at an unit-' an^le. Specimen originally described by MOCQVKRYS, Col. 

 tinoriii. , p. (i 1. I'm. 



(6) Position DP. 



*75!>. Pyrodes speciosus (Longic. ); having two supernumerary legs 

 aiticulating \vith the thorax by a common coxal joint, which is 

 distinct from the nixa of the left middle leg, but is enclosed in 

 tin- same socket with it. In this remarkable case the normal 

 le^ i.s complete, though slightly pushed towards the middle line. 

 The socket in the mesothorax is enlarged posteriorly and dorsal ly 

 so as to form an elongated, elliptical articulation, which lies ob- 

 li'|uely, so that its ventral end is anterior to its dorsal end. The 

 anterior and ventral end is occupied by the coxa of the normal 

 leg, while the coxal joint of the two extra legs fills the space 

 d'.r-al and external to it. Both are capable of being moved 

 independently in the relaxed insect. The extra legs articulate 

 with their coxa by a common double trochanter which has two 

 apis's, from \\hich point the legs are distinct. Their position 

 is dorsal and posterior to the normal leg, being practically that 

 marked DP in the Scheme, and the relative positions of the 

 extra le-s are very nearly those indicated for the Position DP. 

 The leg nearest the normal leg is of course ji right leg in structure, 

 and its plantar and a little of its structurally anterior surfaces 

 an- turned posteriorly. On the other hand, the remoter leg is 

 a true left leg and the ventral surface of its femur is placed 

 almost exactly horizontally. All three legs are complete, but 

 they an- a little shorter and more slender than the middle leg 



of t lie other side. 



This specimen is in the Hope ('ollection at Oxford. 



