METHOD OF DETERMINING GENERA. 131 



black, and so hirsute as to have led Ray (wanting the 

 knowledge of the use of the trophi and posterior shanks) 

 to unite the one he knew with his Bombylii ; their males 

 are fulvous, and the latter have a remarkable elongation 

 of the intermediate tarsi, from one of the joints of which 

 also a tuft of hair or a loose lateral fringe projects, giv- 

 ing them thus a wider expansion, and the use of which 

 is prehensile, the same as that for which the anterior 

 tarsi in some of the Megachiles and in our single Anthi- 

 dium receive their dilatation. This structure has also 

 the effect of adding very considerably to the elegance of 

 their appearance when they are in fine condition. 



The male Apathi can only be distinguished from the 

 male Bombi by familiarity with specific characteristics, 

 or by the examination of the trophi. But the former 

 is the more certain mode of separation, as the trophi 

 in Bombus vary in some species, but not sufficiently to 

 authorize generic subdivison. General appearance will 

 mark where they approximately belong. The length of 

 their antennae sufficiently distinguishes them as males, 

 and they may be taken with impunity in the fingers 

 from flowers for examination, being, like all the male 

 aculeate Hymenoptera, unarmed with stings. The female 

 Apathi may be superficially distinguished from the female 

 Bombi, which they most resemble, exclusively of the 

 generic characters of the convex and subpubescent ex- 

 ternal surface of the posterior tibiae and the trophi, also 

 by their abdomen being considerably less hirsute than 

 that of the genuine Bombi, in which it is entirely covered 

 with dense shaggy hair, whereas in Apathus there is a 

 broad disk upon its surface nearly glabrous. If I re- 

 member rightly, it is the male Apathi only, and not the 

 male Bombi, which emit on capture a pleasantly fragrant 

 odour of attar of roses. 



