28 
BRITISH BEES. 
or prominent ridge, down its centre, lies between these 
eyes, descending from the vertex to the base of the cly- 
peus, or nose, but which is without the function of that 
organ. This clypeus is sometimes protuberant, and from 
shape or armature, characteristic. This part, however, is 
not always distinctly apparent, although a line or suture 
usually separates it above, from the face. At its lower 
extremity the labrum , or upper lip, articulates, over 
which it is sometimes produced; and it extends at each 
lateral apex to the base of the insertion of the mandibles. 
The gena, or cheeks, descend from the vertex laterally, 
behind the compound eyes, to the cavity of the head 
which contains the lingual apparatus, when folded in re¬ 
pose. These cheeks, at their lower extremity, sometimes 
embrace the articulation of the mandibles. 
The antenna, or feelers, are two filamentary organs 
articulating on each side of the face and above the cly¬ 
peus. They comprise the scape (a), or basal joint, and 
(b) the flagellum or terminal apparatus; the latter con¬ 
sists of closely attached conterminal joints, and usually 
forms an elbow with the scape; collectively these joints 
number twelve in the female and thirteen in the male. 
They are all of various relative lengths, which sometimes 
^ aid specific determination. The scape, how- 
ever, is usually much longer than any of the 
la 1 rest, and in some males has a very robust and 
even angulated shape. A description of the 
antennae always enters into the generic charac- 
2 \ ter; they usually differ very materially both in 
F; g . 6.—i. length and form in the sexes. They are often 
ten me 6 filif° rrn (2),butmore generally subclavate (1), 
lifonn ditto; and sometimes distinctly so, and where thev 
a, scape; b, . J 
flagellum, have the latter structure it is found in both 
