PROTECTION AGAINST UNBIDDEN GUESTS. 239 



through. As a matter of fact, however, it is usually easier for the bee to 

 get the honey in the ordinary way, and these arrangements of inflated calyces 

 are rather of the nature of protections against creeping insects, ants, and the 

 like than humble-bees. There are in the European Flora some 300 plants whose 

 flowers are robbed by humble-bees biting through the calyx or corolla. For several 

 of them, which depend entirely upon insects for the transfer of their pollen, this 

 burglarious proceeding is fatal. Fertilization is not accomplished; their ovules 

 atrophy and propagation by seed is impossible. Such plants have flowered in vain. 

 Herein lies a contradiction to the otherwise marvellous harmony which exists 

 between the configuration of plants and animals, a contradiction only explicable 

 on the assumption that these plants, whose honey is taken without concurrent 

 pollination, date back to a time at which humble-bees were absent from the district 

 in question. A Catchfly (Silene Pumilio), the flowers of which are industriously 

 visited by humble-bees, occurs in the Eastern Alps (Taurus). The great majority 

 of these bees decline to enter the flowers properly, but, hanging on to the inflated 

 calyx, bite a hole in it and take the honey. The Catchfly rarely sets seeds, and one 

 may see hundreds of plants together, not one of which has ripened a fruit, although 

 they flowered freely during the summer. At the present time this Catchfly has a 

 very restricted distribution in the Alps, and even in districts where it occurs is 

 sporadic. Nor does it propagate with any vitality. The same is the case with 

 another Catchfly {Silene Elizabethce, of the Southern Alps) and with several species 

 of Aconite and Corydalis. Any one familiar with the facts, although he may not 

 be an enthusiastic supporter of current hypotheses as to the history of the vegetable 

 world, must admit: — (1) That these endemic species are becoming extinct in the 

 Alps. (2) That the humble-bees are to blame for this in that they steal the honey 

 without doing the plants any service in return. (3) That these plants date back 

 to a time at which humble-bees did not frequent the regions where they grow, and 

 at which the flowers needed protection only from creeping insects. 



The bulk of the arrangements, so far described for the exclusion of unbidden 

 guests, occur outside the cavity of the flower, and are directed against creeping 

 animals which climb up from the ground. Those, on the other hand, directed against 

 undesirable winged-insects are situated chiefly inside the flower and take the form 

 of hairs and fringes. These may be arranged either into irregular tufts and woolly 

 plugs, or with greater regularity, into lattice-works, cages, and crowns of hairs. 

 Thus we find a woolly thicket occupying the whole cavity of many bell-shaped and 

 urceolate corollas, as in the Bearberries (Arctostaphylos alpina and Uva-ursi, fig. 

 263 1), or the hairs are confined to the tubular portion of the corolla as in the little 

 a,lpine Primula minima. In the Alpine Roses (Rhododendron hirsutum and 

 ferrugineum) and in several of the Honeysuckles {Lonicera nigra, Xylosteum,, and 

 alpigena, fig. 263 ^), the stamen-filaments and parts of the corolla contribute hairs, 

 which, in the aggregate, make a thicket defending the honey. Often the corolla is 

 quite smooth inside, and the bases of the stamens alone are provided with flocks of 

 hair which screen the nectaries, as in A tropa, L ycium, and Polemonium. In the well- 



