106 BRITISH BEES. 



markably conspicuous for its long and delicately slender 

 antennae in the male^ each joint of which is nodose at 

 its extremity. 



The widely-distributed Nomia seems to abound chiefly 

 in India. It, although neither gay nor large, has, in its 

 males, a distinguishing form of the posterior tibise, 

 which is greatly incrassated or thickened ; a peculiarity 

 of structure found also in some other genera of Hyme- 

 noptera, and in several genera of the Diptera, giving the 

 insects which have it a remarkable gait. 



The singularly anomalous distortion of these posterior 

 legs is conspicuous also in the genus Ancylosceles, which 

 is named in allusion to it. 



Another remarkable peculiarity is to be observed in 

 the above genus, Mesocheira, as likewise in the superb 

 Acanthopus, both of which genera have the spur of the 

 intermediate leg palmated at the extremity, and the 

 latter genus is further distii;guished by its large size and 

 splendid development, and by having the fifth joint of 

 the tarsus of the posterior legs longer than the three pre- 

 ceding united, and covered with a pollinigerous brush as 

 dense as that of the elongate first joint of the same limb. 



But the foreign genera which will be most interesting 

 to the reader will, I expect, be those of Trigona and 

 Mellipona, which, in many peculiarities, seem abortive 

 Apes. They seem nature's first endeavour to construct 

 Apis, for they have an apparently imperfect neuration of 

 the wing, in which the external submarginal cell is un- 

 finished. Their only separating distinction from each 

 other is the difference in their mandibles, which in Mel- 

 lipona are broad and edentate, whereas in Trigona they 

 are also broad but denticulated. In Apis these organs 

 are merely irregularly enlarged at the extremity, and 



