TONGUE AND MOUTH PARTS. 95 



the middle of tongue (G, Plate III.), we note, first, 

 that the strong sheath, sh (from which the gathering 

 hairs have been removed, for the sake of clearness), 

 passes round the tongue to the back, where its edges 

 do not meet, but are continuous with a very thin 

 plaited membrane (pm), covered with minute hairs. 

 This membrane, after passing towards the sides of 

 the tongue, returns to the angle of the nucleus, or 

 rod, over the under surface of which it is probably 

 continued. The rod passes through the tongue from 

 end to end, gradually tapering towards its extremity, 

 and is best studied in the queen, where I trace many 

 nerve threads and cells. It is undoubtedly endued 

 with voluntary movement, and must be partly mus- 

 cular, although I have failed completely in getting 

 any evidence of striation. The rod on the under 

 side has a gutter, or trough-like hollow [cd, the 

 central duct), which is formed into a pseudo-tube 

 (false tube) by intercrossing of back hairs. It will 

 also be seen that;, by the posterior meeting of the 

 sheath, the space between the folded membrane (sd) 

 becomes two pseudo-tubes of larger size, which I 

 shall call the side ducts. 



These central and side ducts run down to that 

 part of the tongue where the spoon, or bouton [b, 

 Plate II. ; K, Plate III.), is placed. This is provided 

 with very delicate split hairs (E, Fig. 24), capable of 

 brushing up the most minute quantity of nectar, 

 which by capillarity, is at once transferred by the 

 fathering hairs (which are here numerous, long, and 

 thin) to two side groove-like forms at the back of 

 the bouton, and which are really the opened out 



