OR, MANUAI< OP THB APIARY. 137 



added, just at the last, some partially digested pollen which is 

 shed when the alimentary canal is moulted with the last larval 

 skin. The fact that undigested pollen is found in the larval 

 food shows that this food is from the stomach, and is not a 

 secretion. It has been suggested that the difference which Dr. 

 Planta and others find in the composition of the larval food of 

 worker, queen and drone larvK is wholly due to this partially 

 digested pollen which is withheld from the inchoate queen and 

 workers. 



There are also large compound racemose or acinose glands 

 (Fig. 59, I h £;)in the head, and also a similar pair (Fig. 58, I g) 



Fig. 58. 



Spitining Qland of Larva, and, cross section of same, after Schiernenz. 



C Gland. ,S Sinus. 



/Duct. D Common duct. 



in the thorax, which are by some thought to be the modified 

 spinning glands of the larva. These four glands unite into a 

 common duct, which passes through the mentum and opens 

 just at the base of tongue on top in the groove between the 

 paraglossae (Fig. 55, C, L, and 56). The thoracic glands were 

 discovered by Ramdohr in 1811, while Meckel also discovered 

 the second pair of cephalic glands, these are the upper h_ead- 

 glands ; Schiemenz is probably correct in thinking that these 

 glands, which are present in all bees, are for digesting the 



