BOMBINATOR. 155 



year the yellow pigment extends to the other parts of 

 the under surface. The bright colours are never fully 

 developed in specimens under 20 mm. body-length. 



The male of this species differs from that of the 

 preceding in the total absence of vocal sacs, the sub- 

 maxillary muscle being undivided ; and in the presence, 

 during the breeding season, of a band of black horny 

 excrescences on the inner side of the third finger as 

 well as on the first and second, and of small round or 

 oval groups of similar excrescences under the penulti- 

 mate phalanx of the third, the second and third, or 

 the second, third, and fourth toes, as first pointed out 



Fig. 58. 



Lower view of fore limb and foot of male, showing nuptial 



excrescences. 



by Bruch in 1863, although their discovery is usually 

 attributed to Ley dig, who first gave a figure of them. 

 The spiny horny excrescences of the upper parts are 

 more developed in the males than in the females, the 

 difference being most marked during the breeding 

 season, the development of these excrescences being- 

 correlated with that of the so-called copulatory or 

 clasping plates which arm the fingers and toes. 



Geographical Variations. — As we have seen above 

 in dealing with the markings of the lower parts, it is 

 possible to correlate some of the variations with the 

 habitat. Thus I think I can in every case recognise 

 specimens from the mountains of the Italian Peninsula, 

 which represent the typical B. pachypus, by the pre- 

 dominance of orange or yellow on the belly and the 

 lower surface of the thighs, its absence or its reduc- 

 tion to spots on the breast, and its absence on the 

 tarsi; the habitus is particularly massive, and the size 

 larger. Specimens from other parts of Europe may be 



