I] 



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 20. Head of Humble-bee (Bombns ag-raritm), with the mouth-parts extended. 

 pa, paraglossse ; li, ligula ; //, labial palpi ; pm, maxillary palpi ; la, lamina of 

 ditto ; 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 



