On the Tongue (Lingua) of some Hymenoptera. 51 



when examined with a power of fifty or more diameters, appears to be 

 denseh^ clothed internally with long flue hairs. Sometimes I have seen 

 in it two parallel rows of air-bubbles, almost contiguous, and seeming 

 to be separated only by a thin partition of fine hairs, and the inter- 

 pretation that I at first gave to this appeai^ance, was that the under 

 surface of the tube was clothed internally with short fine hairs conver- 

 ging towards a median line, and pointing toward the apex. Some 

 transverse sections of a humble-bee's tongue exhibit this appearance 

 almost conclusively. I am not, however, fully convinced, that this is 

 the true interpretation of that which certainly is seen. 



B 



Transverse Section of a Bee's Tongue. 



A, upper surface; B, lower surface; c, orifice of tube; d, tubular rod; e, membraneous sack, 

 not inflated; /, vacant spaces; (7, connection of hairy sheath and tubular rod below. 



In accordance with the usual custom, I have called one part of the 

 mouth organs the mentum. Entomologists generally, so far as I am 

 acquainted with the literature of the subject, call that part mentum^ 

 and that which J have called, as we call it in common parlance, the 

 tongue, they call labium. Kirby and Spence, however, suggest that 

 the part usually called the mentum, is really homologous with the 

 labium of other insects, and should receive that name; and they 

 were led to this conclusion by the belief, that " if the matter was 

 carefully investigated, " the tongue would be found to be attached to 

 the upper surface of the head (at the mandibles, as I understand them), 

 and not to the mentum. The researches above detailed, lend a par- 

 tial confirmation to this view; for, as we have seen, the tongue is a 

 compound organ, the tubular rod being a prolongation of the little 

 piece before mentioned, which is placed before and connected with 

 the mentum, while the hairj- sheath and sack are continuous with 

 the ossophagus, which passes along the upper side of the head, 

 between the mandibles and under the labrum. I have now before 

 me, a specimen in which the tube having been separated from 

 the mentum, the liaiiy sheath membrane has been removed along 

 the upper surface of the mentum and head behind the mandi- 

 bles, back to the occipital foramen, exhibiting the phar3nx closed 

 by the Iwpopharynx in the membrane; the epipharynx (Savigny) 

 being removed with the "labrum. In the hive-bee, the pharynx is 



