NO. 14 SENSE ORGANS ON MOUTH-PARTS OF BEE McINDOO 47 



to the gustatory organs at the base of our tongues, and he thought 

 that the secretion of the salivary glands, always present inside the 

 glossal covering, kept the beakers constantly moist and gustatory 

 stimuli were effected by the saliva changing the honey which passes 

 through the groove in the glossa. 



Joseph (1877) saw taste-pits on the bases of the tongues of speci- 

 mens belonging to nearly all the insect orders, and especially on those 

 of plant-eating insects. 



Kraepelin (1883) thought that he found gustatory organs on the 

 proboscides of flies. These were seen on the inner surface of the 

 cushion of the labellum. From his description they may be the same 

 as the olfactory pores under discussion. 



Will (1885) described the olfactory pores on the tongue, maxilke 

 and labial palpi of the honey bee and various other insects in much 

 the same manner as depicted by the present writer. He called them 

 beaker-shaped organs and imagined that they receive gustatory 

 stimuli because the peripheral ends of their nerves come in direct 

 contact with the food. He saw two groups of them on the base of 

 each tongue, and the number of organs in each group varies as 

 follows : Apis (worker) , about 25 ; Osmia, 14 to 16 ; Bombus, 20 to 24 ; 

 and Ichneumonidse, 12 to 14. About 40 organs were seen in each 

 group on the maxilla? of the Apidae, but very few in the Tenthredin- 

 idae. Will failed to understand the internal anatomy of these organs. 

 He thought the sense cells are multinucleated and that their sense 

 fibers pierce the thin membranes covering the beakers in order to 

 come in contact with the external air. 



Breithaupt (1886) describes the pits or pores found on the base 

 of the tongue of the honey bee. Being unable to make thin sections 

 through these organs, he constructed a schematic drawing of a single 

 pore which shows the sense fiber of the spindle-shaped sense cell run- 

 ning to the extremely thin and transparent membrane which covers 

 the pore. 



Vom Rath (1886) seems to have found organs similar to the olfac- 

 tory pores in the labium of millipedes (Chilognatha) . Each organ is 

 porelike and is two-thirds filled with a pear-shaped bundle of nerve 

 fibrillar which pass through the fine pore aperture and come in con- 

 tact with the external air. The same author (1887, 1888) seems to 

 have seen the same organs on the palpi of beetles. 



Janet (1904) found a constant group of olfactory pores on each 

 labial palpus, two rows on the tongue, and some on the pharynx of 

 ants. Those seen by him on the pharynx perhaps really lie on the 



