
690 THE AMERICAN NATURALIST. (VoL. XXXVI. 
strongly “telescoped,” the strange adult mandible, with its 
lack of dentation, its pointed tip, and its great length (easily 
attained by extension of the longitudinally compressed organ 
as discovered within the pupal sheath). Thus the transforma- 
tion of larval parts into pupal, and of pupal into imaginal, is 
obvious, and the homologies between larval and imaginal parts 
are firmly founded on ontogenic basis. 
COLEOPTERA. 
The Coleoptera, like the Neuroptera, have biting mouth 
parts in both larval and imaginal stages, but the differences 
are usually greater, and the general metamorphosis is on the 
whole more radical. 
Anatis 15-punctata (Figs. 6-8). — The accompanying figures 
made from a study of the mouth parts of Anatis 15-punctaia 
illustrate the relations between larval and imaginal mouth 
parts of a member of the order. The larva (Fig. 6) have 
strongly chitinized, sharp-toothed mandibles (md.), maxilla 
(mx.) with single terminal lobe (mx./.), rather large four- 
segmented palpus (mzx.f.), and fleshy liplike labium (Z.), with 
fused terminal lobes and short one-segmented palpus (Z-) 
inserted on a segment-like projection. In the adult (Fig. 7) 
the mandibles (md.) are shorter and heavier, the maxillae (zx.) 
have both terminal lobes, galea (ga.) and lacinia (/.), distinct, 
and four-segmented palpi (mr.p.), the distal segment being 
much broader than the others. The labium (//.) is rather elon- 
gate, with distinct basal sclerites (submentum and mentum), 
fused terminal lobes, and short three-segmented palpi (Z.). 
The small size of the larval head precludes such dissections 
as were easily made in the case of Corydalis, and the thick- 
ness and opacity of the chitinized cuticle of the head makes 
it impossible to clear specimens and study the forming imagi- 
nal head within, a method very successfully used in the cases 
of the honeybee and digger wasp (see postea). The develop- 
ment of the imaginal head and mouth parts had to be studied 
by means of sections, and here again the firmness of the head 
wall offered a serious obstacle to satisfactory work. I have 
