MOUTH OF HUMBLE-BEE. 



Panurgus (Fig. 17), Halictoides (Fig. 18), and Chelos- 

 toma (Fig. 19), we see various stages in the elon- 

 gation of the lower lip, until at length it reaches 

 the remarkable and extreme form which it now 

 presents in the hive and humble bees (Fig. 20), and 



FIG 2< 

 **, . 

 ditto 



.Head of Humble-bee (Bombus agrorum), with the mouth-parts extended, 

 paraglossa; ; li, ligula ; pi, labial palpi ; pm, maxillary palpi ; la, lamina of 

 > ; tnt, mentum ; ft, stipes ; md, mandibles ; c, cardo ; o, eye. 



which enables them to extract the honey from 

 almost all our wild flowers. No bees, however, 

 have the proboscis so much elongated as is the 

 case with some butterflies and moths; perhaps, 

 as Hermann Muller has suggested, because the 



C 2 



