INSECTS IN RELATION TO PLANTS 209 
Modifications of Insects with Reference to Flowers.— 
While the manifold and exquisite adaptations of the flower for 
cross pollination have engaged universal attention, very little 
has been recorded concerning the adaptations of insects in re- 
lation to flowers. In fact, the adapta- eo" 
tion is largely one-sided; flowers have as 
become adjusted to the structure of in- 
sects as a matter of vital necessity—to 
put it that way—while insects have had 
no such urgent need—so to speak—in 
relation to floral structure. They have 
been influenced by floral structure to 
some extent, however, and in some cases 
to a very great extent, as appears from 
their structural and physiological adapta- 
tions for gathering and using pollen and 
nectar. 
Among mandibulate insects, beetles 
and caterpillars that eat the floral en- Pollen-gathering hair 
: ies - from a worker’ honey 
velopes show no special modifications fee, with a pollen grain 
attached. Greatly mag- 
for this purpose; pollen-feeding beetles, 7% 
2 nified. 
however, usually have the mouth parts 
densely clothed with hairs, as in Euphoria (Fig. 261). In 
suctorial insects, the mouth parts are frequently formed with 
reference to floral structure; this is the case in many but- 
terflies and particularly in Sphingide, in which the length of 
the tongue bears a direct relation to the depth of the nectary in 
the flowers that they visit. According to Muller, the mouth 
parts of Syrphide, Stratyomyiide and Muscidze are specially 
adapted for feeding on pollen. In Apidze, the tongue as com- 
pared with that of other Hymenoptera, is exceptionally long, 
enabling the insect to reach deep into a flower, and is exqui- 
sitely specialized (Fig. 127) for lapping up and sucking in 
nectar. 
Pollen-gathering flies and bees collect pollen in the hairs of 
the body or the legs; these hairs, especially dense and often 
