EXTREMITIES. 



297 



Soon after the appearance of the thoracic limbs, rudimentary 

 appendages can be seen on the abdominal segments also (Figs. 136 

 Pa P§> an d 137 A, flj-ffg). These, in most cases, exactly correspond 

 in position and in the manner of their development to the limb- 

 rudiments of the preceding segments, so that we may consider them 

 as fully equivalent to the latter. The first statements as to the 

 presence of limb-rudiments on the first abdominal segments were 

 made by Rathke (for Gryllotalpa), and the first mention of the 

 presence of limb-rudiments on all the abdominal segments by 



J 



— a 



Fig. 14".— Two stages in the development of the germ-band of Melolontlta (after Graber). 



A, stage with eight pairs of abdominal limb-rudiments (al-a 8 ). B, older stage ; the germ- 

 band is very much broadened, a 1 , limb belonging to the first abdomiDal segment (in 



B, widened out into a sac) ; ofi, limb belonging to the eighth abdominal segment ; an, anus ; 

 at, antenna; bg, ventral chain of ganglia ; fir, brain; 1, labrum ; m, mouth; md, mandible; 

 rax', first, m:u", second maxilla ; p\ p-, p3 first, second, and third thoracic limb ; s, lateral 

 strand of the ventral nerve-cord ; st, stigma ; x, point of attachment of the sac-like first 

 abdominal limb. 



Butschli (No. 11, Apis). These statements have recently repeatedly 

 been verified in numerous Insects (for the literature on this point see 

 especially Graber, Nos. 25 and 30, Wheeler, No. 91, and Carriere, 

 No. 15). The first point to be noted is, as Graber has shown, that, 

 in the Orthoptera and Coleoptera, as well as in some Hemiptera, 

 the appendages of the first abdominal segment, as compared with 

 those of the subsequent segments, are more massive and in later 

 stages develop characters peculiar to themselves, while, in the Lepi- 



