92 THE ANATOMY OF THE HONEY BEE. 



acinus consists of a solid mass of several small cells, which are pene- 

 trated by a large number of fine, chitinous ducts, arising in the neck 

 of the acinus from the common duct of the gland. These follicular 

 ducts can be very clearly shown by treating a part of the gland with 

 weak caustic potash, which dissolves the protoplasm of the cells 

 and brings out the bunch of ductules very clearly. 



The fact that these glands are entirely absent in the drone and at 

 best rudimentary in the queen shows that they must in some way be 

 connected with the special functions of the worker. Schiernenz (1883 ) 

 and Cheshire (1886) have shown that their development in the dif- 

 ferent species of bees is in proportion to the social specialization. 

 They vary from a group of cells opening by separate ducts upon the 

 pharyngeal plate to the highly developed condition they present in 

 the honey bee. The writer questions, however, whether these authors 

 did not mistake the median pharyngeal glands of these lower genera 

 of bees for rudimentary representatives of the lateral glands. Bordas 

 states that the former occur in all Hymenoptera, but Schiernenz and 

 Cheshire did not seem to recognize them. The bumblebees (Bombus) 

 have them almost as well developed as the honey bee (Apis), espe- 

 cially the large females. In the genus Psythirus they are similar to 

 those of Bombus but are smaller, while in such genera as Andrena 

 and Anthophora they are rudimentary or consist of a few scattered 

 cells. Both Schiemenz and Cheshire have thus argued strongly that 

 these glands of the pharynx are the organs that produce the brood 

 food. On the other hand, Schonfeld (1886) has made an equally 

 strong plea in favor of the ventriculus as the producer of this impor- 

 tant material. He believes that the brood food, especially royal 

 jelly, is regurgitated chyle. Both Schonfeld and Cook (1904) fed 

 bees in a hive some honey containing powdered charcoal and later 

 found this in the brood food in the comb cells, thus apparently con- 

 firming its ventricular origin. However, the charcoal that got into 

 the cells might have come from the mouth, the oesophagus, or the 

 honey stomach. It, of course, could not have gone through the 

 stomach walls and entered the pharyngeal glands, as proved by Dr. 

 J. A. Nelson, of this Bureau, from microtome sections of bees fed on 

 lampblack. The arguments, then, in favor of the stomach and the 

 pharyngeal glands seem equally strong, and perhaps the truth is, as 

 occurs in so many such cases, that both sides are right — ^that the brood 

 food is a mixture of chyle from the stomach and of secretion from 

 the pharyngeal glands. 



Arnhart (1906) seems to adopt the position that the brood food 

 is chyle which has been acidified by the addition of an acid from the 

 glands. He states that the acid reaction of the royal jelly is due to 

 the presence of three- fourths of 1 per cent of tartaric acid. The 

 contents of the ventriculus, on the other hand, and for that matter 



