FLOWERS WITH CONCEALED NECTAR 113 
As I have pointed out (‘ Bliitenbesucher,’ I, pp. 16-17), not only do the flowers 
of this class present a considerable advance on those of the previous group, but their 
visitors also attain a distinctly higher level of specialization with regard to pollination 
than do the visitors of flowers with partly concealed nectar. The less intelligent 
short-tongued insects, finding it more difficult to get at nectar which is completely 
concealed than that which is more or less exposed, are much less important here than 
in the two preceding classes. Long-tongued insects, on the other hand, visit these 
flowers far more. 
The honey-bee may almost everywhere be observed sucking the flowers 
belonging to this class: its proboscis (6 mm. long) conveniently reaches the nectar 
concealed in the base of the flower, the position of which it quickly discovers. Its 
nearest relatives, the humble-bees, also appear in swarms as visitors, and parasitic 
humble-bees eagerly seek out the abundant though hidden nectar, which they can 
reach without trouble, with the kelp of their long proboscis. The other long-tongued 
bees join them in this quest. 
Since the nectar is usually concealed at a depth of only a few mm., it is easily 
reached by short-tongued bees and long-tongued wasps, as well as by the Bombyliidae 
and Syrphidae among the Diptera. The nectar, owing to its deeper position, can 
also be more conveniently sucked up by Lepidoptera than that of flowers belonging 
to the preceding classes. 
This is more difficult for short-tongued flies (Muscidae and others) and wasps. 
For the same reason beetles are even more infrequent visitors: those that do occur are 
usually small forms, with slender bodies, enabling them to creep right into the flower, 
where they get at the nectar, without conferring any benefit. The coleopterous 
visitors are sometimes pollen-eating beetles, which only occasionally effect pol- 
lination. 
Some flowers of this class are specially interesting, as being visited by definite 
species or groups of insects. 
Wherever Lythrum Salicaria grows, for example (see p. 95), the bee Cilissa 
melanura JVy/. is found upon it as a guest, and indeed scarcely visits any other plant. 
Symphoricarpos racemosus is in some districts almost exclusively visited by wasps, 
while Scrophularia nodosa is everywhere a well-marked wasp flower, as are Cotone- 
aster vulgaris and Lonicera alpigena (according to Herm. Miiller’s observations in 
the Alps). These wasp flowers will be more fully described when hymenopterid 
flowers are dealt with (cf. pp. 119-20). 
Veronica Chamaedrys and a few other species of the same genus are hover-fly 
flowers, as the delicate mechanism of pollination is here only properly brought into 
action by flies of the kind (see Floral Class, Fb, pp. 135-6). 
Not a few flowers conceal the nectar so deeply that they form a transition 
between classes C and H, so that they may be designated by the symbol CH, 
e.g. Rubus Idaeus and saxatilis; Euphrasia officinalis, salisburgensis, and minima ; 
Goodyera repens. The following belong to CHb: Polygala comosa and alpestris, 
Polemonium caeruleum, Vaccinium Vitis-Idaea and uliginosum, Calluna vulgaris. 
Saxifraga oppositifolia belongs to the transitional stage CL: Hermann Miller 
(‘Alpenblumen,’ pp. 25 and 31) includes the following in CF: Oxalis Acetosella, 
Pyrola uniflora and rotundifolia. 
DAVIS I 
