12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



of their expanded ends fit exactly on the midribs of the maxillary 

 galeae and allow the latter to slide between them. When the proboscis 

 is folded (fig. 3 B) the mandibles are crossed behind the labrum 

 against the bases of the flexed galeae, and thus hold the proboscis 

 snugly against the head. 



Passively the mandibles, when partly opened, form a conduit for 

 the discharge of nectar or honey and of brood food from the mouth. 

 According to Park (1925), "the honey is forced out over the dorsal 

 surface of the folded proboscis between the mandibles which are 

 held well apart" ; and in a personal communication Frank E. Todd 

 of the United States Bureau of Entomology and Plant Quarantine 

 says, ''feeding of royal jelly, and of honey and pollen, to the larvae 

 is done through the mandibles." 



The mandible of the queen (fig. 3 J) is of about the same length 

 as that of the worker (F), but is bilobed distally and much wider at 

 the base; it has a concavity on the inner face of the apical lobe, but 

 there is no groove leading up to the orifice of the mandibular gland. 

 The posterior surface is clothed with more numerous and longer 

 hairs than the worker mandible, but in both castes of the female the 

 mandibular hairs are unbranched. The mandible of the drone (G) is 

 relatively and absolutely smaller than that of either the worker or 

 the queen ; its distal part is narrow, provided with a small apical tooth, 

 and has a niesal depression from which a faintly marked groove leads 

 up to the base of the jaw. The hairs of the drone mandible are par- 

 ticularly long and numerous, and, in contrast to those of the female 

 mandible, are nearly all of the plumose variety. 



The mandibular gland of the worker (fig. 3 F, MdGld) and the 

 queen is a large sack lying between the facial wall of the head and 

 the apodeme of the adductor muscle of the mandible. The gland in 

 the worker extends upward to the level of the antennal bases, and 

 in the queen is even larger. In the drone the mandibular gland is 

 but a small vesicle at the base of the jaw. The secretion of the 

 mandibular glands of the bee is said to serve for softening wax, but 

 corresponding glands in other insects presumably have a "salivary" 

 function in connection with feeding. 



The maxillae. — The two maxillae (fig. 3 A) lie at the sides of the 

 median labium rather than before it. The long siipital sclerites {St) 

 of the maxillary bases are implanted proximally in the membrane of 

 the proboscis fossa on the back of the head, and are suspended from 

 the hypostomal margins of the fossa by the slender cardines (Cd), 

 which also are contained in the fossal membrane. The free distal 

 part of each stipes bears a long, broad, tapering galea (Ga), a large, 



