LEPIDOPTERA 171 
Some of the extra-European Sphingidae, especially tropical species, have a 
proboscis 140-160, or even up to 250 mm. long. There are corresponding flowers 
with corolla-tubes or spurs 6-12 cm, in length (Oenothera Missouriensis, Habenaria, 
Gardenia, Randia, Portlandia, Exostemma, Oxyanthus, Angraecum sesquipedale). 
Fritz Miiller found the proboscis of Macrosilia Cluentius Cr. to be about +m. long. 
The choice of flowers by Lepidoptera is generally correlated with the length of 
the proboscis, forms in which it is long preferring flowers with deeply seated nectar. 
Corresponding to hawk-moths (Sphingidae) which have a greatly elongated 
proboscis, there are special forms of flowers that are mainly or entirely adapted 
to their visits, and for this reason Loew describes these moths as eu¢ropous insects 
in contrast to the other hemz¢ropous Lepidoptera (‘ Blumenbesuch, II, p. 127). The 
majority of the hawk-moths fly about on mild summer evenings at dusk or night. 
And as such evenings are not very common in our climate, the period of flight of these 
and other moths is very restricted. Hermann Miiller supposes (‘ Fertilisation,’ p. 67) 
that either the shortness of the time when the weather is suitable for their flight, or 
the pursuit of bats, may be the cause of the extraordinarily rapid and stormy move- 
ments of these moths. This peculiarity of crepuscular and nocturnal Lepidoptera 
is a decided advantage to the flowers they visit, for the amount of pollination effected 
by every visitor in a given period of time is in proportion to the shortness of its stay 
at each flower and the rapidity of its flight to the next. Hawk-moths demonstrate, 
in a most marked manner, the advantage of rapid pollination for plants. Hovering 
before the flower, they introduce their long proboscis into the corolla-tube, and after 
a short delay hasten with stormy flight to another flower. Among nocturnal flowers, 
therefore, most are adapted to these very Lepidoptera, having the nectar concealed 
at the bottom of such long tubes or spurs that it is accessible to them alone 
(‘ Fertilisation,’ p. 67). 
While most hawk-moths visit flowers at dusk, the species of the genus Macro- 
glossa also fly about in the daytime’, and do so in the same stormy manner as their 
nocturnal relatives. A distinction can therefore be made between zght hawk-moth 
and day hawk-moth flowers. 
I have described in the case of Macroglossa stellatarum (‘ Bl. und Ins. auf. den 
nordfries. Ins.,’ p. 80) the way in which hawk-moths visit a flower.— The insect 
comes with impetuous flight in the bright sunshine of high noon to the flowers of 
Lonicera Periclymenum, halts and hovers with trembling wings in front of the 
entrance to the flower, and sinks the extended (22-28 mm. long) proboscis deep 
- into the corolla-tube, thus effecting cross-pollination. The proboscis is withdrawn 
as quickly as it was introduced, and the insect forthwith flies straight as an arrow 
to another flower, there to repeat the same actions. The species of Sphinx, and 
other genera, when visiting a flower at dusk or night behave precisely in the same 
way as this diurnal hawk-moth. 
With what skill and persistence the Sphingidae suck deeply hidden nectar from 
their flowers, and with what fidelity they adhere to the species once selected, thus 
1 Many Noctuidae also sometimes fly by day, e.g. Plusia gamma. Hermann Miller (‘ Alpen- 
blumen,’ pp. 64 and 66) observed in the Alps several crepuscular and nocturnal moths flying by day 
to Gymnadenia conopea and G. odoratissima. 
