132 MR. MILLER CHRISTY ON THE 
As to the small bees forming Group 2: there can be no doubt that they 
can, and actually do, pollinate some of the flowers. Nevertheless, it is 
certain that the number of occasions on which they do this are few—so few 
that one cannot possibly suppose they can pollinate adequately the flowers of 
any of our Primulas. 
Further, certain of these short-tongued bees (being unable to reach the 
nectar in the ordinary manner, by way of the entrance to the corolla-tube), 
have been observed to bite a hole in the side of the tube, just above the level 
of the top of the calyx—a proceeding which enables them to steal the 
nectar, but without effecting pollination, unless, possibly, of the short-styled 
flowers. Darwin observed this, many years since, in the case of the Cowslip *. 
Knuth says t that, in Germany, the flowers of this species are “ fairly often 
perforated by humble-bees." Müller says} of Bombus terrestris (tongue 
7-9 mm.) that it 
makes a hole in the corolla-tube [of the Oxlip], a little above the calyx, sometimes 
biting it with its mandibles, sometimes piercing it with its maxillæ, and so reaching 
the honey with its tongue. I have sometimes seen this bee, before boring the flower, 
make several attempts to reach the honey in the legitimate way. 
Jules Macleod, in 1880, watched this operation being performed on Oxlips 
by two species of Bombus (one not named : the other given as B. muscorum, 
but more likely B. terrestris), in the woods near Ghent, in Belgium. In 
some woods, he says §, it was hard to find a flower the tube of which had not 
been perforated: in other woods quite near, scarcely a flower had been 
pierced—the difference depending, he says, on the abundance or scarcity of 
the bee he identifies as B. muscorum. He adds that, by listening, it was not 
difficult to hear the noise made by the bee whilst tearing the hole in the 
corolla-tube. 
Prof. Weiss, on two occasions in the spring of 1903, observed humble- 
bees, “not sucking at the flower [of Primrose], but moving all over the 
corolla, both at the front and at the back of the flower, apparently 
endeavouring to obtain the honey by illegitimate means" ||. 
It is only when we come to consider the large long-tongued humble-bees 
and butterflies forming Group 1 that we find ourselves dealing at last with a 
fair number of insects (about fifteen species), all of. which are known to 
visit the flowers in fair numbers and are fully capable of pollinating them 
effectively. That they actually do the latter to an appreciable extent can 
not be doubted. 
* See ante, p. 108. t ‘Flower Pollination,’ iii, p. 66. 
i ‘Fertilization of Flowers,’ p. 384. $ Bull. Acad. Roy. Belge, n. s., 1. (1880), p. 30. 
il See New Phytologist, ii. (1903), p. 102. 
