On the Tongue (Lingua) of some Ilymenoptera. 47 



ter's exptM-iraents seem to negative Biirmi ester's suggestion of the 

 office of the sucking stomach, tliey have no bearing on the structure of 

 a bee's tongue. Again, the tongue is terminated by what Reauraer calls 

 a "button," but wliich is really a flap or sucker-like expansion of the 

 tube, which we shall see, further on, does exist, whatever may be its 

 office. Its use in a sucking instrument can be perceived, but what is 

 its use in a lapping one ? Besides, as stated by Reaumer, the tongue 

 certainly does seem to be tubular. One not accustomed to the appear- 

 ance of objects under the microscope, would certainly pronounce it 

 tubular. How is this appearance to be explained, if it is illusory ? 

 Some hairs have been called tubular, and this has been said to be an 

 incorrect interpretation; yet it is in one sense correct, for the hair is 

 tubular though the tube is filled with the " pith." A glass rod some- 

 times appears to be tubular, but this is an illusion caused b3' refraction. 

 This can not cause the appearance of the bee's tongue, because though 

 not flat, it is not cylindrical, and does not refract the light sufficiently^ 

 to produce the illusion. If the tongue is not tubular, no explanation 

 of its tubular appearance has been given. The extensible maxillae of 

 the beetle, Chauliognothus pennsf/lvanicus, De Gur., present a nearly 

 analogous structure; they are membraneous, cylindrical, and clothed 

 with hairs very much as in the bee's tongue, but there is no appear- 

 ance of a tube, simply because there is no tube. 



In the bee's tongue there is an appearance of a tube. It can not be 

 an optical illusion arising from refraction. In fact nothing is easier- 

 of demonstration than that it is really a tube. Reaumer came very 

 near demonstrating it, but he stopped just at the critical point in his 

 observation. As stated by him, and as observed by ever}- one, who 

 has ever observed a bee's tongue, when the tongue is extended to its 

 full extent by pressure upon the mentura, the outer envelope of the 

 tongue, which we shall call after Reaumer, the "hairy sheath ," opens 

 along its lower surface, from the base to about the opical third of its 

 length, in the hive and humble bees, but, almost to the apex in Zylo- 

 copa Carolina, and through this opening there protrudes, what Reau- 

 mer calls the "Membraneous Sack," and, in bees just taken from 

 flowers, this sack is, as observed by Reaumer, usually full of nectar. 

 Reaumer mentions, that he could see the nectar flow down into it, from 

 the direction of the mentum. If he had pressed the tongue in the 

 other direction, from the apical part towards the base, he would have 

 seen, at least I have seen, the nectar flow in the other direction, along 

 the slightly grooved upper surface of the mentum, beneath a mem- 

 brane, which is in fact a continuation of the " hairy sheath, " back 

 under the labrum , thus jyroving a direct communication between the 

 opening under the labrum, and the membraneous sack, and showing 

 Ihat the membraneous sack is a prolongation of the oesophagus, or at 



