of Rhynchophorous Coleoptera. 293 
In Rhynchophora the prothoracic sutures are obliterated ; 
there is no separation between the prosternum and episterna, 
and very rarely between the latter and the pronotum ; the coxal 
cavities, frequently confluent, are always closed behind, by the 
epimera, which become connate on the median line, enclosing 
the hind part of the prosternum, thus cutting it off completely 
from the mesothoracic segment. 
Fig. 5 represents this arrangement of parts in a Brenthide, 
in which family the extreme limit of degradation by linear ex- 
terision is reached. Fig. 6, under surface of prothorax of a 
Calandride (Rhynchophorus). Fig. 7, ditto of Cryptorhynchus. 
Fig. 8, ditto of Balaninus. Fig. 9, ditto, Ophryastes. Fig. 10, 
ditto, Thecesternus. Fig. 11, ditto, Dendroctonus. 
When the coxe are contiguous, the point of the prosternum 
is visible behind them, but is none the less perfectly enclosed 
by the growth of the side pieces to the median line. 
Another evidence of the inferiority of type of the Rhyncho- 
phora, which has not been mentioned, is seen in the functions 
performed by the beak, which in the lower groups, especially in 
the female, becomes greatly elongated. The occurrence of cor- 
neous exserted ovipositors in other orders of insects is not rare ; 
a few species of Coleoptera (certain Valgus, for example) have 
the last abdominal segment prolonged, simulating such an organ; 
but it was reserved for the Rhynchophora to exhibit a degrada- 
tion of type by which a function, peculiarly appropriate to the 
posterior extremity of the body, is performed by the head—the 
elongated beak becoming, in fact, the ovipositor. 
Thus the inferiority of grade, evidenced in other series of 
Coleoptera by the softness of the integuments or by the perma- 
nence of larval forms, chiefly in the abdomen and coxe, is in 
