ROSACEAE 355 



Visitors. — I observed the following in the island of Fohr. — 



A. Coleoptera. Nitidulidae: i. Meligethes sp. B. Diptera. (a) Mmcidae: 



2. Anthomyia sp. j; 3- Drymeia hamata Fall.; 4. Lucilia caesar Z. ; 5. L. sp. ; 

 6. Musca sp. ; 7. Onesia sepulcralis Mg. \ 8. Sarcophaga carnaria L. (i) Syrphidae: 

 9. Eristalis arbustorum Z. ; 10. Helophilus floreus Z. 5; 11. H. pendulus Z. ; 

 12. Syrphus ribesii Z. C. Hymenoptera. Apidae: 13. Apis mellifica Z. ; 14. 

 Bombus lapidarius Z. ; 15. B. terrester Z. ; i6. Coelioxys acuminata NyL\ 17. C. 

 rufescens Z^^ ; 18. Collates picistigma Thorns.; 19. Megachile centuncularis Z. $. 

 D. Lepidoptera. Rhopalocera: 20. Epinephele janira Z. ; 21. Lycaena semiargus 

 Roit. To these must be added a fossorial wasp, 22. Ammophila sabulosa Z., 

 noticed in 1897 in the island of Amrum, though not previously seen by me on the 

 North Frisian Islands : all skg. 



Alfken observed the following in Juist. — 



A. Diptera. (a) Straiiomyidae : i. Sargus cuprarius Z. (F) Syrphidae: 2. 

 Syrphus trilineatus Z. B. Hymenoptera. Apidae : 3. Bombus lucorum Z. 5, freq., 

 skg. ; 4. B. muscorum F. 5, do. ; 5. B. terrester Z. 5, do. ; 6. Colletes marginatus 

 Z. J, freq., po-cltg. and skg. ; 7. Megachile maritima X. $, skg. and po-cltg., 5 skg. 



Verhoeff saw a small Muscid in Norderney. 



Schenck noticed the following bees in Nassau. — 



I. Ceratina cyanea A'. ; 2. Macropis labiata F., and the var. fulvipes F.; 



3. Stelis breviuscula Nyl. 



Schletterer observed the following Hymenoptera at Pola. — 



(a) Apidae: i. Bombus variabilis Schmiedekn. \ 2. Eucera interrupta Baer. ; 



3. Halictus minutus K. ; 4. H. morbillosus Krchl. ; 5. H. quadricinctus F. ; 6. H. 



scabiosae Rossi; 7. H. variipes Mor. ; 8. Osmia aurulenta Pz. ; 9. Prosopis genahs 



Ths. (i) Sphegidae : 10. Tachysphex nitidus Spin. 



H. de Vries observed, in the Netherlands, 2 humble-bees (Ned. Kruidk. Arch., 



Nijmegen, 2. ser., 2. deel, 1875), — Bombus subterraneus Z. 5, and B. terrester Z. 5- 



839. R. odoratus L. (Knuth, ' Bloemenbiol. Bijdragen.') — This is a 

 Canadian species, often cultivated in German gardens as an ornamental shrub. 

 The flower mechanism is as follows. — At first the numerous still unripe anthers 

 completely cover the immature stigmas ; those of the outer stamens then dehisce, 

 and pari passu the stigmas become freed by an increase in the diameter of the 

 flower. An insect dusted with pollen will therefore necessarily effect crossing if it 

 alights in the middle of the flower, and when such an insect creeps to the mature 

 peripheral anthers it covers its under-surface with pollen afresh. Dehiscence of 

 the anthers goes on centripetally, so that the pollen of the innermost may effect 

 automatic self-pollination by falling upon the stigmas should insect-visits fail. In 

 spite of the large size of the flower (40-50 mm. in diameter), and of the deep red 

 colour of the petals, the number of visitors is small. Automatic self-pollination is 

 not always effective in Germany, for I have very rarely observed the setting of fruits. 



Visitors. — I have seen Bombus lapidarius Z. S, po-cltg., in the island of Riigen. 

 Loew has noticed a humble-bee in Silesia (' Beitrage,' p. 51) ; also B. hypnorum Z. 

 , skg., in the Berlin Botanic Garden. 



840. R. Idaeus L. (Herm. MuUer, 'Fertilisation,' pp. 226-7; Kirchner, 

 'Flora V. Stuttgart,' pp. 450-1; Knuth, ' Bl. u. Insekt. a. d. Ins. Riigen.') — In 

 the flowers of this species the small narrow petals, which Kerner says drop off on 

 the second day of anthesis, remain erect, according to Hermann MuUer's account, so 



A a 2 



