THE ATJMENTARY (WNAL AND TTS GLANDS. 



91 



dorsally to above the antenna:', where it turns posteriorly and con- 

 tracts into the much narrower esophagus {(E). Attached to its 

 walls are numerous suspensorial muscles, whose contraction must 

 expand the pharyngeal cavity, while the latter may be contracted 

 by the sheet of muscles surrounding its walls. In this way the 

 pharynx is undoubtedlv able to perform a sucking action, by means 

 of which the liquid foods are taken into the mouth. Its lateral 

 walls are strengthened by two long, chitinous rods (figs. 11 B and 

 19, /,) , which arise from a median anterior plate in its floor (fig. 10, .s). 

 The anterior end of this plate is prolonged into two free, tapering 

 lobes which hang down over the lower rim of the mouth. The plate, 

 in the worker, and the leases of the rods are shown in ventral view, 

 removed from the pharyngeal wall, in figure 43 D. Near where the 

 rods join the plate are two long, chitinous pockets (mm), opening 

 above which receive the ducts of the two large glands {]G1) lymg 

 within the anterior part of the head. Between these two pockets is a 

 transverse row of cells (4^/), which have l)een described by Bordas 

 (1895) as the "sublingual glands,'^ but this name is not appropriate 

 in insects, for, while the gland in question may be suggestive of the 

 sublino-ual salivary gland of vertebrates, it does not he beneath the 

 tono-ue^or lingua 'of the bee. Although the pharyngeal plate lies 

 upon the floor of the true mouth, it is not, as already explained (p. 

 44) the equivalent of what is properly called the tongue, lingua, or 

 hvpopharvnx in other insects-this organ being absent m most 

 Hymenoptera. The onlv suggestion the writer can make, however 

 is'to call this group of cells the ventml or median ventral pharyngeal 

 qlamJ in distinction to the large lateral glands. A comparative view 

 of the pharyngeal plate and its accessory parts in the drone is given 

 in flexure 43 E. The plate itself (n) is shorter than m the worker, 

 audits anterior lobes are smaller. The lateral glands and their 

 receptacula are entirely absent, but the median glands (4<^?).«re 

 much larger than those of the worker. Bordas says that each acinus 

 of the latter o-lands in both the worker and the drone is provided 

 with a fine, sinuous canaliculus, and that these tmy ducts open 

 separately in two bundles on the lateral parts of the pharyngeal 

 plate. The lateral glands are present in the queen, but are very small 



and rudimentary. •, , j i? 



Fspecial interest attaches to the large lateral pharyngeal glands ot 

 the worker {Ry^tem No. 1 of Cheshire, the .upraccrelral glands 

 of Bordas), because they are regarded by many as the source of the 

 brood food and the so-called " royal jelly," which is fed to the larva, 

 and to the adult queens and drones by the workers. Each consists 

 of a long coiled string of small ovate follicles attached to one median 

 duct (fio- 43 A) and the two are intricately packed into the anterior 

 .nd upper parts of the head (figs. 10 A, 19, and 42, IGl), Each 



