82 



TEXT-BOOK OF ENTOMOLOGY 



extensions, like small aprons, behind ; and by these the nectar reaches the front 

 of the tongue, to be swallowed as before described." 



Cheshire then settles the question which has been in dispute since 

 the time of Swammerdam, whether the bee's tongue is solid or tubu- 

 lar. He agrees with Wolff that the duct is a trough and not a 

 tube, and proves it by a satisfactory experiment. He remarks : 



"Bees have the power, by driving blood into the tongue, of forcing the rod 

 out from the sheath, and distending the wrinkled membrane so that in section 

 it appears as at H, Fig. 86, the membrane assuming the form of a pouch, given 



ant 



br 



06 



FIG. 87. Longitudinal section through the head of the honey bee, 9. just outside of rip-lit an- 

 tenna: in/t, antenna with three muscles attached to mes, mesocephalic pillar; cl, clypeus ; Ibr, 

 lahruin ; 1, chyle-gland (system no. 1, of Siebold) ; o, opening of the same; oc, ocellus ; ///, brain ; 

 n, neck ; th, thorax ; oe, (esophagus ; .v.rf 2 , s.d 3 , common salivary ducts of systems ~2 and '.', ; /, sali- 

 vary valve ; c, cardo ; ph, pharynx ; mx', labium ; mx. 'p, labial palpi ; mt, mentum ; mx, maxilla ; 



>, hypopharynx ; s, boutou. After Cheshire. 



in full length at A. It will be seen at once that this disposition of parts abol- 

 ishes the side ducts, but brings the central duct to the external surface. The 

 object of this curious capability on the part of the bee is, in my opinion, to 

 permit of cleaning away any pollen grains, or other impediment that may collect 

 in the side ducts. The membrane is greasy in nature, and substances or fluids 

 can be removed from it as easily as water from polished metal. If, now, the 

 sides of a needle, previously dipped into clove oil in which rosanilin (magenta) 

 has been dissolved, so as to stain it strongly red, be touched on the centre of 

 the rod, the oil immediately enters, and passes rapidly upwards and downwards, 

 filling the trough." 



Does the hypopharynx represent a distinct segment? The facts which 

 suggest that the hypopharynx may possibly represent a highly modified pair of 

 appendages, arising from a distinct intermaxillary segment, are these : Ileymons 

 plainly shows that, in the embryo of Lepisma, the hypopharynx originates as a 

 transverse sc^mcnt-likr fold in front of the 2d maxillary segment, and larger 

 than it, and though he does not mention it in his text, it appears like the rudi- 

 ment of a distinct segment ; the hypopharynx of Ephemerida; arises and remains 

 separate in the nymph from the labium (see Ileymons' Fig. 29, and there are 

 two lateral projections; see also Fig. 72, and Vayssiere's view that it may 

 represent a pair of appendages ; Kolbo also regards it as representing a third 

 pair of maxillte, his endolabium, p. 213). Though what is called an unpaired 



