ONAGRARIEAE 449 



already dusted with pollen. As the four stigmas roll back so as ultimately to touch 

 the anthers before these have lost all their pollen, autogamy takes place if insect- 

 visits fail. 



Visitors. — On the North Frisian Islands I only noticed po-cltg. or po-dvg. 

 insects (Apis, Bombus terrester Z., Eristalis, Scatophaga). I also observed skg. 

 insects at Kiel, i. e. Macroglossa stellatarum L. (in the dusk), and Bombus hortorum 

 L. 5 (in the forenoon). Loew saw Apis, po-cltg., in the Berlin Botanic Garden. 



Herm. Miiller gives the following list. — 



A. Diptera. Syrphidae: i. Eristalis arbustorum L., very freq., po-dvg.; 

 2. E. nemorum Z., do. ; 3. E. tenax Z., do. B. Hymenoptera. Apidae: 4. Apis 

 mellifica Z. g, skg. and po-cltg. ; 5. Bombus agrorum F. j, skg. ; 6. B. lapidarius 

 Z. 5, do. ; 7. B. sylvarum Z. 5, do. ; 8. CoUetes daviesanus K. 5, po-cltg. ; 9. Pan- 

 urgus calcaratus Scop. 5 and J. C. Lepidoptera. Sphingidae: 10. Macroglossa 

 stellatarum Z., skg. 



Redtenbacher records the Elaterid Corymbites sulphuripennis Germ, for Austria. 



1058. O. muricata L. ( = 0. biennis Z., according to the Index Kewensis). — 

 Kerner states that the flower mechanism in this North American species agrees with 

 that of O. biennis. 



1059. O. biennis L., x O. muricata L. — 



Visitors. — Heinsius saw the following in Holland (Bot. Jaarb. Dodonaea, 

 <}hent, iv, 1892, p. 115). — 



Three humble-bees, skg. and effecting pollination (Bombus cognatus Steph. 5 ; 

 B. hortorum Z. 5, S and 5 ; B. rajellus K. 5). A small bee (HaHctus leucozonius 

 Schr. S) skg., and occasionally effecting pollination. Empids (Empis hyalipennis Fall. 

 i and 1 ; E. pennaria Fall. 5) and a Syrphid (Eristalis nemorum Z. J), do. 



1060. O. Lamarkiana Ser. (=0. biennis Z., according to the Index Kewensis). 

 (Stadler, ' Beitrage zur Kennt. de Nekt. u. Biol. d. Bl.,' Berlin, 1886.) — The flower 

 mechanism of this species agrees with that of O. biennis. The very fragrant Lepi- 

 dopterid flowers are protandrous. Stadler says that the nectary lines the base of 

 the corolla-tube, and, like the inner surface of two-thirds of the tube, is beset 

 with unicellular barrier-hairs. The upper part of the tube is lined with a felting 

 of hairs. Nectar is secreted so abundantly that it usually ascends to a height of 



, 5 mm. The pollen-grains are bound together by threads of viscin, and remain 

 hanging between the anthers. Self-poUination is rendered impossible by this peculiar 

 fixing arrangement. Each pollen-grain has rounded poles, from which two or 

 more small bunches of threads project. These interweave with those of neighbouring 

 grains, and thus the pollen, ' entangled as in a spider's web into strings and clumps,' 

 remains on or between the anthers, and cannot be scattered by the wind nor by 

 the action of gravity. 



Visitors. — Heinsius observed the following in Holland (Bot. Jaarb. Dodonaea, 

 Ghent, iv, 1892, pp. 11 3-1 5). — 



Four humble-bees, skg. (Bombus agrorum F. j and 5 ; B. cognatus Steph. ; 

 B. hortorum Z. 5 : B. lapidarius Z. 5 and 5)> and 3 hover-flies, po-dvg. (Eristalis 

 honicola Z. 5 ; E. intricarius Z. 5 ; Pelecocera tricincta Mg. V). 



1061. O. missouriensis Sims. (Knuth, ' Bloemenbiol. Bijdragen.') — The 

 North American species cultivated under this name in our gardens bears moth 



