99 
The Life of the Individual 
segments coalesce to form the adult head, the next three 
the typical insect thorax, and the remaining ones, usually 
twelve 1 in number, form the abdomen. The thorax of the 
adult bee is not typical, as will be explained later. 
Fate of parts of the embryo. 
Some of the head appendages of the embryo disappear 
early, being rudimentary organs. For example, the append¬ 
ages of the second segment become the antennae while those 
of the third disappear in insects, but in Crustacea ( e.g. 
shrimps and lobsters) form the second antennae. Several 
of the segments of the primitive insect head are not recog¬ 
nizable in the bee. In the adult insect, these segments fuse 
completely and by growth of various parts are so distorted 
that an examination of the adult head does not suggest 
segmentation and, without a study of the developmental 
stages, this segmental origin would be unsuspected. 
The three thoracic segments are fused in the adult bee 
but, since the three pairs of legs arise from them, the seg¬ 
mental origin is suggested. The wings arise as secondary 
outgrowths or appendages, dorsal to the legs, from the two 
posterior thoracic segments and do not correspond with 
other appendages. In the adult bee, the first abdominal 
segment is also fused with the true thoracic segments to 
form the part known as the thorax, which therefore does 
not correspond exactly with the thorax of lower orders of 
insects. This fusion also occurs in most of the other Hy- 
menoptera. The remaining posterior segments foim the 
abdomen of the adult but not all of the segments remain 
visible to the outside. In the adult worker and queen bee, 
the five posterior segments are turned in to form a pocket 
around the sting and anus. In the drone, only four segments 
are so turned in. 
The embryo, just before leaving the egg, shows no rudi¬ 
ments of antennae or legs, these temporarily disappearing. 
1 Two of these segments are obscure and in later stages there appear to 
be present only ten. 
