86 Mouth Parts of Workers. 



imated, form a tube which is continued by a membrane to the 

 mouth opening of the pharynx, just between the bases of the 

 jaws. This tube forms the largest channel through which 

 nectar passes to the pharynx. . The labium varies in length 

 from .23 to .27 of an inch. By the sub-mentum (Fig. 22 

 A, o) and two chitinous rods (Fig. 22, A, b, b) it is hinged to 

 the-maxUlse. The base or mentum (Fig. 22 A, rn) is tubu- 

 lar. The lower part of the tube is thick with chitine, the upper 

 part membranous. This tube opens into the pharynx and 

 extends into the tongue. From the mentum extend the 

 tongue or ligula (Figure 22, Ajf), the paraglossse (Fig. 22, A, 

 p, p), whose sack-like bases connect with the tube of the 

 mentum, and the labial palpi (Fig 22, k, k), which, in arrange- 

 ment, form and function, resemble the maxiUse. The tongue 

 consists of an annulated sheath (Fig. 22, B and C, S) which 

 is slitted along its under side to near the end. This is very 

 hairy. Within this is a tubular rod (Fig. 22, B, and C, B) 

 which is also slitted along its under surface. This extends 

 beyond the sheath, where it becomes an imperfect funnel 

 (Fig. 22, /). A thin colorless membrane (Fig. 22, C, s, s) 

 connects the slitted margins of the rod with those of the 

 sheath. This, with the sheath, forms a sack which may be 

 distended (Fig. 22, B) with nectar, as it has connection with 

 the tube of the mentum, though it is closed anteriorly. The 

 tubular rod connects with the sack and with the tube of the 

 mentum at the base of the ligula. 



While the bee is sipping liquid food, the tongue alternately 

 pushes out and draws back for a short distance, which motion 

 is effected by muscles at its base. This may be analogous to 

 swallowing. When not in use the tongue is partially drawn 

 into the mentum, and with the labial palpi and maxillae is 

 bent under the head. 



When bees can get at nectar in quantity, they suck it 

 through the extemporized tubes formed by approximating the 

 maxillae and labial palpi. Deep down in flowers they only 

 sip through the funnel and tubular rod. When a liquid is 

 spread out thin, I think they lap or wipe it up, when it passes 

 through the slit into the tubular rod, and thence to the 

 pharynx. 



Connected with the tube in the mentum, and thus with 

 the mouth, is a tube which leads to two pairs of glands 



