HYMENOPTERID FLOWERS 119 
Lycoctonum JZ. var. pyrenaicum Ser. in the Pyrenees. It may be added that this 
observer also saw many individuals of Bombus Gerstaeckeri Mor. 2 seeking the 
nectar of this flower. This species (Schmiedeknecht, ‘Apidae Europ., p. 304) is 
identical with B. opulentus Gers¢. (Knuth, ‘ Bliitenbesucher,’ IT, p47). 
Another instance is afforded by Corydalis solida and C. cava. The only 
nectar-sucking insect effecting cross-pollination, and observed on the two species 
of Corydalis (by Herm. Miiller in Lippstadt, by myself in Kiel, and by MacLeod in 
Ghent) was Anthophora pilipes § and 9, which with its long proboscis (19-21 mm.) 
can conveniently reach the nectar secreted and concealed in the base of the spur. 
‘It visits the Corydalis flowers in such numbers and so diligently that it suffices for 
the pollination of all of them.’ Hermann Miiller further observed two hairy hover- 
flies (Bombylius major Z., and B. discolor Ag.) sucking in the normal way, 
though they were only nectar-thieves, and did not liberate the floral mechanism. 
It is also known that Cerinthe alpina is pollinated exclusively by Bombus 
alticola, and Delphinium consolida by B. hortorum. 
An intermediate stage between Bee Flowers and Humble-bee Flowers is con- 
stituted by Bee-Humble-bee Flowers (Hbh) which, e.g. in Calamintha alpina, 
possess two different floral forms, one of which is regularly visited by humble-bees 
only, while the nectar of the other is accessible even to bees with a proboscis less 
than 7 mm. long. In this species, according to Hermann Miiller (‘Alpenblumen,’ 
pp. 319 and 320), there are large-flowered and small-flowered stocks, both of them 
hermaphrodite and protandrous. In the flowers of the former the corolla-tube is 
1omm. long, in those of the latter it is only 6mm. The relations are similar 
in the case of Alectorolophus major and minor, which Hermann Miiller regards © 
(‘ Fertilisation, pp. 454-6) as different forms of one species (Rhinanthus Crista- 
galli Z.). The corolla-tube in ‘ major’ is g-10 mm. long, in ‘minor’ 7-9 mm. 
Wasp Frowers (Hw) also permit other insects to reach their nectar, and may 
be pollinated by them. They have, therefore, already been mentioned among flowers 
with concealed nectar to which they belong, so far as the shelter of nectar is 
concerned. 
In many regions the visitors of Symphoricarpos racemosus A/ichx. are mostly 
True Wasps. Hermann Miller (‘ Fertilisation,’ p. 292) observed that in Thuringia 
more than nine-tenths of all the visitors belonged to five species of Vespidae, while 
in Westphalia, where wasps are less abundant, the visits of honey-bees were more 
numerous. I myself noticed in Thuringia that Vespa saxonica was very commonly 
to be seen sucking nectar from snowberry flowers, while in Schleswig-Holstein (chiefly 
on the North Sea coast, and the Baltic coast from Riigen to Geestemiinde) I 
observed that the visitors and pollinators of this plant’ were almost exclusively bees 
and humble-bees. Scrophularia nodosa is a much more characteristic wasp flower. 
Not only in Europe, but also in North America, wasps have been noticed as the 
most important floral visitors of this plant. It appears, however, that this visitation 
is not uniform at all times of the year. In Holstein, for example, I found that this 
1 After the completion of my manuscript, I saw on July 20, 1897, at Heringsdorf, in the 
Island of Usedom, that Symphoricarpos racemosus was visited by numerous sucking species of wasps, 
as well as by Apis and Bombus lapidarius Z. $. 
