26 THE ANATOMY OF THE HONEY BEE. 



of gonapophyses arises in a median depression on the ventral side of 

 the segment while the true appendages are latero-ventral. Hence, 

 the evidence is very much against this theory and the gonapophyses 

 appear to be special secondary processes of the body. wall. 



All insects do not have ovipositors of the sort described above. 

 Flies, beetles, moths, and butterflies do not. Such insects simply 

 drop their eggs from the orifice of the oviduct or deposit them in 

 masses upon ■the external surfaces of various objects. In some of 

 the flies, however, the terminal segments are long and tubular and 

 entirely telescoped into one another. They are hence capable of 

 being protruded in the form of a long tapering tube having the open- 

 ing of the oviduct near the tip. This enables the insect to deposit its 

 eggs in deep crevices, but the structure is not a true ovipositor — it is 

 simply the abdomen itself stretched out. 



Insects breathe through a series of small holes situated along each 

 side of the body. These breathing apertures are called spiracles and 

 they lead into a system of internal air tubes called trachew. There 

 are nearly always 10 spiracles present on each side of the body. Two 

 are located on the thorax, the first between the prothorax and the 

 mesothorax, the second between the mesothorax and the metathorax, 

 while the other eight are situated on the first eight abdominal seg- 

 ments. Some embryologists believe that the spiracles of the pro- 

 thorax move forward in early embryonic life and unite with each 

 other in front of the hypopharynx to form the salivary opening, their 

 tracheae constituting the salivary ducts. 



After this review of the general external structure of insects we 

 may proceed to a more detailed account of the parts and organs of 

 the honey bee. 



III. THE HEAD OE THE BEE AND ITS APPENDAGES. 



The head of an insect, as already explained, is a composite organ 

 formed of six or seven primitive segments, each of which, except the 

 first, typically bears a pair of appendages (fig. 2). The antennae are 

 developed from the embryonic appendages of the second segment, 

 the mandibles from the fourth, the maxillae from the sixth, and the 

 second maxillae, or labium, from the seventh. The appendages of 

 the third segment disappear in early embryonic life while those of 

 the fifth segment, when the latter is present, fuse with a median 

 tonguelike lobe of the next segment to form the hypopharynx of 

 the adult. 



1. THE STKUCTUEE OF THE HEAD. 



The general appearance and outline of the head of a worker bee 

 are shown from before and behind by figure 9, A and B. In facial 

 view the head is triangular, with the apex below. The side angles 



( 



