PART u.] THE INSECTS WHICH VISIT FLOWERS. 35 
of Toxotus occur chiefly on flowers, rarely on shrubs; the four 
remaining genera confine themselves to flowers. In proportion 
to the extent to which these forms confine themselves to a floral 
diet, are the structural characters displayed in them which mark 
off the Lepturide from other Cerambycide, and which fit them for 
_ feeding on honey, whether superficially or more deeply placed, viz. 
the elongation of the head forwards, a neck-like constriction 
behind the eyes, and consequently the power to direct the 
_mouth forwards, the prothorax elongated and narrowed anteriorly, 
. and, as I have found by a comparison of the mouth-organs, the 
development of hairs upon the lobes of the maxilla. 
a wi 
MANS 
Fic. 3,—Adaptations in Beetles for feeding on honey. 
1.—Leiopus nebulosus, L. never visiting flowers. Head bent downwards, no neck behind the 
eyes, prothorax broad, lobes of the maxilla (1b) furnished with bristly hairs. 
2.—Clytus arietis, L., occasionally visiting the flowers of Umbelliferee and Rosacew. Head less 
‘bent downwards, less broad behind the eyes ; prothorax longer and narrower ; outer lobe of maxilla 
(galea, 2b) set with longer hairs, 
3.—Leptura livida, F., exclusively anthophilous,—Umbellifere, Rosiflore, Composite, Convol- 
vulus, and others. Head elongated and directed forwards, with a distinct neck behind the eyes ; 
thorax still narrower ; both lobes of the maxilla (galea and lacinia) with long hairs (3d). 
4.—Strangalia attenuata, L., exclusively anthophilous, and able to lick honey from the corolla of 
Scabiosa arvensis (4 to 5mm. in length). Characters those of the preceding species, but the pro- 
thorax is still longer and still more narrowed anteriorly ; both lobes ofthe maxilla have long 
hairs (4b). 
All these modifications form so complete and gradual a series, 
from those Cerambycide which never visit flowers, and those which 
‘can only lick superficially placed honey, up to Strangalia attenuata, 
which can reach the honey in Scabiosa arvensis at the base of 
tubular florets 4 to 6 mm. long, that the little steps by which natural 
selection has operated may be clearly traced. 
The order of Coleoptera is thus of special interest, as affording 
‘us the first tendency of insects towards floral diet, and the first 
corresponding modifications. We see how, in the most diverse 
families, accustomed to widely varying nourishment, single species 
have become habituated, first partially, then exclusively, to a floral 
diet, and that then, by natural selection, structural changes have 
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