66 Riley — Preside iit'uiJ Address. 



I'^xamination of these parts in other species of Apis fails to indicate any 

 particular modification or deviation in structure from nieUiJiat. In Api.'< 

 inclicu no dili'erences whatever can be discovered ; in A. dorsata the leg is 

 somewhat more hairy and a few hairs occur on the outer surface of the 

 tibia. In . I. //o;-m the smallest S])ecies known, the spines on the apex of 

 the tibia are somewhiit shorter and stouter and the hairs forming the cor- 

 biculum are somewhat less regular in length and arrangement. 



1'his shitement of Ihe structure of these parts in the species of Apis will 

 enable us to compare intelligently the similar jiarts in those genera most 

 nearly allied to them, trat-ing the variation through these to the more 

 widely divergent forms. The genera JMelipona ancl Tiigona include bees 

 which are closest to Apis in genei'al structure and habits, and agree also iu 

 the absence of the tibial spines of the posterior legs. We tind, as might be 

 infe]-)-ed, a very close corresi)ondence in the poliiniferous apparatus, which, 

 in :dl essential details, is practically the same as in Apis. The pollen-col- 

 lecting combs on the inner surface of the tii'st tai'sal joint are al)sent, or 

 rather their ]3la(^e is supplied by a uniform clothing of shoit stiff spines 

 which are not arranged transversely in rows, as in Apis, but serve the same 

 purpose. This joint also ditfers in shape from that in Apis, by being sud- 

 <lenly narrowed or excavated toward the base so that the nip|.ers noted in 

 the former genus for the removal of the wax ai-e ])ractically wanting, 

 although the row of stiff spines at the a])ex of the tibia is still present, but 

 somewhat reduced. A very peculiar tuft of strong, curved spines occurs, in 

 the two genera mentioneil, at the anterior outer angle of tiie tibia. This 

 has no counterpart in any other bees and its function is problematical. 



In the case of Bombus, the lowest of the social bees, there is at once a 

 greater divergence from A))is and at the same time a resemblence to it in 

 certain features of the hind legs and pollimferous ai)parMtus. The tibial 

 spines ai'e very strongly and ^irominently develoj)ed, allying this genus to 

 the solitary bees and other Hymenoptera, but the general structure of the 

 tibia and lii'st tarsal joint is practically identical with that of Apis, and the 

 tai'sal joint in this ]«irticular doe-^ not ])resent the diverg(>nce which was 

 note<l in tlie case of the genera IMeliiiona and Trigona, but has the broadly 

 truncated basal margin forming the lower blade of the nippers, even more 

 strongly developed than in Ajiis. The pollen-collecting spines on tiie inner 

 face of the tarsal joint are uniformly distributed over the surface, ]ir;icti<'ally 

 as in the two genera la.st mentioned (Melipona and Trigona). The border- 

 ing hairs of the eorbiculum are somewhat stronger and more abundant, but 

 in all essential details the structure is identical with the same in Apis. 



The solitary bees of the genus Anthophora, which is somewhat nearer 

 A|)is than any other, jn-esent distinct ti'aces of the specialized poliiniferous 

 apparatus of this last. The enlargement (jf the tibia and of the first tarsal 

 joint is quite marked, and the eorbiculum is imperfectly indicated by the 

 longer growth of hairs on the edge of the tibia, the face of the latter lieing 

 also covered with shorter hairs. The brush or ])ollen comb on the inner 

 surface of the tarsal joint is pi'actically the same as in Fxanlnis. The small 

 row of S]jines at the apex of the tibia are entirely wanting, and the nippers 

 at the junction of the tibia and metatarsus are not particularly noticeable; in 

 f;ict this sti'ucture is not seen in anj' except the social bees which alone pro- 

 duce and use wax in their economy. The genus Rlelissodes jiresents a dis- 

 tinctly wider divergence from Apis, in that the hairy vestiture on the outer 

 surface of the tibia and metatarsus is eciually long and dense over the entire 

 surf^ice, showing little if any a]i])roach to the eorbiculum, which, as we have 

 seen in Anthoi)iiora, begins with the shortening of the hairs on the outer 

 face of the til)ia. In other ])articulars the bees of this genus are similar to 

 Anthoi)hora, an<l in both genera the ])ollen collectetl is carried intersjieised 

 among the hairs of the tibia and tarsus, being doubtless emptied or combed 

 into them tWini the brush of the inner surface of the first tarsal joint, and 

 probably removed again by the same brush in storing it in their larval cells. 



Going stiU lower in the scale of bees, we find in Perdita a yet wider 



