LIBRARY

COLEOPTERA 621
first sternite is always absent although the first tergite is present and the
second sternite is absent or fused with the third in many of the PO­
L YPHAGA. The ninth and 10th sternites are missing. Thus when viewed
from the venter a variable number of sternites may be discernible. The
number of visible tergites may also be important in classification.
4. Coxre and Coxal Cavities; The shape and position of the coxa! and the coxal
cavities play an important role in separating the families and genera.
maxillary palpus--'
mesosternal episternum •••
coxal cavity--__ ,' ___ _
metasternal epimeron --- - , --
lacinia,
galea \
! !
spurs
.·::llbigl sputs
FIG. 175. The common black calosoma showing ventral side with principal parts indicated.
(From Insects of Western North America.)
The CDxre may be globular, cone-shaped, elongate, egg-shaped, narrow or
broad; contiguous, approximated, or far apart; transversely or obliquely
situated; coxre of hind legs fiat Wld immovably incorporated into the