PART IIL. | THE MECHANISMS OF FLOWERS. 541 
attaching them by their secretion. Smaller bees and flies which 
are too large to pass freely through the orifice and too weak to 
force their sides apart, must as a rule perish of hunger within the 
labellum. I have repeatedly found Andrena parvula, K. 9, dead 
within the labellum, and also the following flies: Hmpis punctata, 
F., a Cheilosia (Syrphide), an Anthomyia (Muscidae), and considerable 
numbers of Spilogaster semicinera, Wied. (Muscidew). Small 
beetles (Meligethes) are often able to creep freely out of the 
labellum, but sometimes they are held fast by the sticky pollen and 
remain to perish. 
Cypripedium barbatum is believed by Delpino to be fertilised by 
flies. Delpino found flies within the labellum of some cultivated 
plants, which afterwards set seed (178, 567). 
Cypripedium caudatum is believed by Delpino to be fertilised by 
snails (178), 
THE ADAPTIVE MODIFICATIONS OF ALPINE ORCHIDS COMPARED 
WITH THOSE OF THE LOWLANDS. 
A review of the Orchids that I have observed upon the Alps 
shows that, above the limit of trees, almost the only species which 
occur are those adapted for Lepidoptera, while in the lower regions 
forms adapted for all kinds of visitors occur. The following 
species occur in greater abundance above the level of trees, or are 
restricted entirely to that region: (1) Orchis ustulata, (2) O. globosa, 
(3) Gymnadenia conopsea, (4) G. odoratissima, (5) G. albida, (6) 
Peristylus viridis, (7) Nigritella angustifolia (N. suaveolens, as being 
probably a hybrid, cannot be included), (8) Platanthera solstitialis, 
(9) Chameorchis alpina. Of these, six (1, 2, 3, 4, 7, 8) are un- 
doubtedly, and two (5, 6) (from the narrow.entrance to the spur) 
in all probability, are fertilised by Lepidoptera. While we thus 
find that of the loftier Alpine Orchids at least two-thirds, but 
probably eight-ninths, are adapted for Lepidoptera, in Westphalia 
we find that, of thirty-five species,! at most six? are adapted for 
Lepidoptera, and most of these are very sparingly visited by 
them (609). 
1 Orchis pyramidalis, O. morio, O. mascula, O. laxiflora, O. coriphora, O. militaris, 
O. tridentata, O. sambucina, O. latifolia, O. maculata, Gymnadenia conopsea, G. 
albida, Platanthera bifolia (solstitialis), P. chlorantha, Peristylus viridis, Herminium 
Monorchis, Ophrys muscifera, O. apifera, O. aranifera, Epipogon Gmelini, Cephal- 
anthera pallens, C. ensifolia, C. rubra, Epipactis latifolia, E. microphylla, E. viridi- 
flora, E. atrorubens, E. palustris, Listera ovata, Goodyera repens, Spiranthes autum- 
nalis, Malaxis paludosa, Liparis Loeselii, Cypripedium Calceolus. - 
? Orchis pyramidalis, Gymnadenia conopsea, G, albida, Platanthera bifolia (solsti- 
tialis), P. chlorantha, Peristylus viridis. Aw 
