REPRODUCTION BY SEED 173 
the flower-stalks—e.g., Silene, Lychnis—or by obstruct- 
ing hairs on the calyx or at the entrance of the flower. 
The extra-floral nectaries which occur on some plants— 
é.g., plum, laurel—may serve the purpose of diverting 
these marauders. 
3. Flowers with fully-concealed honey. 
(a) Honey concealed in short flowers—e.g., geranium, 
willow-herb, bramble, veronica, mint, ling, etc. This group 
excludes the short-tongued insects entirely, the flowers 
being pollinated by long-tongued flies and medium- 
tongued bees, butterflies, and moths. These insects are 
larger and much more skilful in extracting honey than 
the smaller short-tongued insects, and they usually confine 
their attention to one species of flower as long as possible. 
In this way there is less waste of pollen and a greater 
certainty of pollination. 
(6) Flowers in which the honey is concealed at the 
bottom of long tubular corollas, or spurs. These are the 
most specialized of entomophilous flowers, and are only 
visited by the longest-tongued insects—bees, butterflies, 
and moths. Many of the largest and most irregular 
flowers are visited by the humble-bee—a strong, heavy 
insect with a long tongue. This bee has the vicious habit 
of boring through the base of the corolla and illegitimately 
removing the honey without pollinating the flowers—e.g., 
bell-heather, dead-nettle, toadflax, foxglove, Canterbury 
bell, columbine. Through the holes thus made smaller 
insects can enter and complete the plunder. To this class 
belong the larger Leguminose, Scrophulariacee, and 
Labiate, many orchids, and those flowers pollinated 
exclusively by butterflies and moths—e.g., evening-prim- 
rose, Lychnis, species of Silene, tobacco-plant, honey- 
suckle, primroses, ete. 
The Pollinating Insects. 
1. Bees (Hymenoptera).—Bees are either short-tongued 
(ground - bees), medium-tongued (hive - bees), or long- 
tongued (humble-bees). They collect both honey and 
pollen. The pollen is usually rolled up and carried away 
in little packets on the hind-legs. Bees are the most 
important of all pollinators, not only because of the 
length of their tongues, but also because of their strength, 
