FLOWERS WITH EXPOSED NECTAR 109 
In accordance with the position of the nectar, flowers of this class are chiefly 
visited by insects with a short proboscis: short-tongued wasps and flies predominate, 
but to these must be added beetles with equally short proboscis, and flies (Syrphidae) 
with proboscis of medium length, and more rarely bees with proboscis of medium 
length. All other insects are relatively unimportant. Even the honey-bee, so active 
everywhere else, is seen here comparatively seldom: apparently the small quantity of 
pollen and nectar offers it too little attraction, and even less to its allies with still 
longer proboscis. Lepidoptera, in which the long proboscis is ill-adapted for sucking 
up the flat layer of nectar, are extremely rare guests, even in the Alps, where such 
insects abound. (Cf. Knuth, ‘Die Besucher derselben Pflanzenart in verschiedenen 
Gegenden,’ I, p. 13.) 
Fic. 20. Flowers with exposed nectar. (1) Pimpinella rubra Hoppe. (2) Saxifraga aspera Z. 
(3) Gentiana lutea Z. 7. Nectary. 
Hermann Miiller (‘Alpenblumen,’ pp. 481-4) arrives at similar conclusions with 
regard to alpine flowers with exposed nectar: those which are pure yellow, yellow 
with orange spots, greenish-yellow, or white, are principally visited by short-tongued 
insects (85 % of the visitors), in particular by Muscidae, while bees and Lepidoptera 
are relatively very infrequent (only 15 %). The same also holds for the reddish 
Umbelliferae (Meum Mutellina, Pimpinella rubra), while the more intensely red 
Azalea procumbens, which secretes nectar abundantly, is mainly visited by floral 
guests with a more specialized sense of colour, i.e, Lepidoptera, bees and hover- 
flies (80 % of the visitors), while Muscidae are less numerous (20 %). In many 
species of Saxifraga, in Veratrum, and in Lloydia, the insect guests are so pre- 
dominantly Diptera, that Hermann Miiller (op. cit., p. 483) united them into 
a special group distinguished by the symbol AD (Fly flowers with fully exposed 
