242 ANGIOSPERMAEDICOTYLEDONES 



lower, nectar-bearing part is directed obliquely upwards, while its upper part is 

 horizontal. This curve not only protects anthers, stigma, and nectar from rain, but 

 also affords a bee's proboscis the most convenient position for sucking. The limb 

 of the corolla consists of a surface 3 mm. high and 4 mm. broad, divided into five 

 lobes. The lowest of these forms an alighting-platform, and gives standing-room to 

 small, nectar-seeking bees. Four rows of bristles, directed obliquely outwards, oblige 

 the visitor to insert its proboscis into the space between them. When thus inserted, 

 it first brushes against the anthers (which are covered by a circlet of hairs) and then 

 the stigma, but is not dusted with pollen, or only very slightly so, for the dehisced 

 surfaces of the anthers are directed obliquely downwards towards the base of the 

 flower, so that the proboscis must twist these surfaces a little further back. In 

 consequence of the narrowness of the corolla, the insect, in creeping back, presses 

 the anthers in the opposite direction, and their dehisced surfaces touch and dust its 

 proboscis, the end of which is wet with nectar, so that pollen easily adheres. On 

 visiting another flower, the bee brushes some of this off" on to the stigma, which 

 is situated behind the anthers in the corolla-tube, and its proboscis is dusted anew 

 on being withdrawn. Insect-visits therefore generally eff"ect cross-pollination. The 

 two lower of the four anthers, however, lie so close to the stigma that some of their 

 pollen easily reaches it, bringing about automatic self-pollination (which is eff"ective) 

 should these visits fail. Besides flowers with properly developed, ripe anthers, there 

 are others in which only two anthers are fertile. If the two longer stamens are 

 reduced, self-pollination is of course favoured, and if the two shorter ones, only 

 cross-pollination is possible. 



Visitors. Burkill and Willis observed the following at Cambridge (' Flowers and 

 Insects in Great Britain,' Part I). 



A. Diptera. Syrphidae : i. Platycheirus sp., skg. ; 2. Syrphus sp., skg. 

 B. Hymenoptera. Apidae: 3. Apis mellifica Z., freq., skg.; 4. Bombus agrorum 

 F., do. C. Lepidoptera. Rhopalocera : 5. Lycaena icarus Rott, freq., skg. 



The following were recorded by the observers, and for the localities stated. 

 Buddeberg (Nassau), 4 bees, skg. i. Halictus flavipes K t>', 2. H. lugubris 

 K. $ ; 3. H. nitidus Schenck 5 ; 4. H. quadricinctus K. 5. Knuth (Kiel), the 

 humble-bee Bombus pratorum Z,, skg., and 2 hover-flies, skg. Eristalis sp., and 

 Syritta pipiens Z. Herm. Miiller (Alps), the honey-bee, a humble-bee (Bombus sp.), 

 and a butterfly (Epinephele sp.). Schenck (Nassau), the bee Halictus pauxillus 

 Schenck. Schletterer (Pola), 2 bees Anthidium stxigatum Pz., and Ceratina cucur- 

 bitina Rossi. Alfken (Aquileja), 4 bees i. Ceratina cucurbitina Rossi, j and J, skg. ; 

 2. C. cyanea K. $ and $, skg. ; 3. Halictus morio F. 5 and S ; 4. H. virescens Lep. 

 5, very common, skg. and po-cltg., J, rare, skg. MacLeod (Pyrenees), 5 humble- , 

 bees, 5 sp. of Halictus, 3 butterflies, 3 hover-flies, and a Bombyliid (Bot. Jaarb.: 

 Dodonaea, Ghent, iii, 1891, pp. 323-4). Loew (Berlin Botanic Garden), 2 bees 

 Apis mellifica Z. j, skg., and Halictus cylindricus F. t, do. 



2214. V. hastata L. xV. officinalis L. 



Visitors. Loew (Berlin Botanic Garden) observed 2 bees, skg. Apis mellifica 

 Z. 5, and Halictus sexnotatus K. 5. 



3215. V. urticifolia L. 



Visitors. Loew (Berlin Botanic Garden) observed the humble-bee Bombus 

 teiyester Z. 5, skg. 



