1918] 



Segmentation of Abdomen of Bee 



The presence of a telson or anal segment in insects seems to 

 be well established on the evidence afforded by the Odonata 

 and Ephemerida, as well as on theoretical grounds (Heymons 

 1896). The abdomen of the honeybee may therefore be con- 

 sidered as consisting of 12 segments. There is, however, in the 

 honeybee embryo some direct evidence indicating the presence 



-GngI 



Gng9.!l 



Fig. 2. Nervous sj^stem of mature larva. Br, brain; Gng 1-11, abdominal ganglia 

 1-11. Abdominal segments indicated by numerals. From camera drawing 

 of a dissection. 



of an anal segment. At Stage XII (text Fig. lA) the ventral 

 hypodermis just cephalad of the proctodaeum is indented inter- 

 nally by a deep notch or transverse groove, internally by a 

 shallower one, directly opposite to one another and reducing 

 the intervening hypodermis to one layer of cells. These notches 

 may readily be interpreted as corresponding to intersegmental 

 constrictions and therefore as marking the limits between the 

 11th abdominal and anal segments. Vestiges of this separation 

 are also to be seen in later stages, but disappear by the time 

 embrj'onic development is completed. 



