LABI AT AE 297 



turning towards and touching each other. The two outer anthers turn their dehisced 

 sides downwards. The style lies against the posterior wall of the corolla, and is so 

 long, that the stigmatic branches, which mature simultaneously with the anthers, lie 

 either close behind the two inner anthers, or slightly below them. Automatic self- 

 pollination takes place in either case. Later on the two outer stamens diverge so far 

 that their anthers project laterally between the upper and lower lips. The inner 

 stamens diverge very little. The style next droops so far downwards that the stigma 

 is brought into the mouth of the flower. Conditions are now favourable to cross- 

 pollination, but insect-visits are so few that automatic self-pollination takes place with 

 tolerable regularity. 



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

 stated. — 



Kirchner, the beetle Meligethes, and Thrips. Hoppner (Bremen), 5 bees — 

 I. Andrena convexiuscula K.^; 2. Apis; 3. Halictus calceatus Scop. 5; 4. H. 

 leucozonius Schr. 5 ; 5. H. morio F. j. 



2331. S. recta L. (Herm. MuUer, ' Alpenblumen,' p. 312, ' Weit. Beob.,' Ill, 

 pp. 49-50; Loew, ' Bliitenbiol. Floristik,' pp. 392, 395; Kirchner, 'Flora v. Stutt- 

 gart,' p. 627 ; Schulz, 'Beitrage,' II, p. 197.) — The yellowish-white flowers of this 

 species possess nectar-guides in the form of two longitudinal purple lines each side 

 of the margin of the upper lip, and several rows of purple spots on the lower lip. 

 Nectar is abundantly secreted by the large, fleshy base of the ovary, and concealed at 

 the bottom of the corolla-tube. This is 7-8 mm. long, and its lower part is directed 

 obliquely upward : a circlet of stiff hairs protects the nectar. The upper, wider part 

 of the corolla-tube bends slightly outwards, thus taking the form which aff'ords the 

 most convenient position for sucking to the proboscis of a humble-bee. 



The flowers are strongly protandrous. The anthers of the two shorter stamens 

 mature first, turning their pollen-covered surfaces downwards, so that a bee probing 

 for nectar must brush against them with its back. They subsequently turn outwards 

 and downwards, and are replaced by the two longer ones, which now expose their 

 pollen-covered surfaces to visitors below the middle of the upper Up. The style 

 elongates when these are shrivelled, so that the diverging stigmatic branches assume 

 the position previously occupied by the anthers. When visited by insects, therefore, 

 cross-pollination is ensured. Automatic self-pollination is excluded. 



Warnstorf describes the pollen-grains as white in colour, globular when examined 

 in water, smooth, transparent, with very finely granular contents and delicately striated, 

 37-5 to 45 /i in diameter. 



Visitors. — Schletterer either gives the following bees for the Tyrol (T.) or 

 observed them at Pola (P.). 



I. Anthidium manicatum Z. (T. and P.); 2. A. septemdentatum Llr.; 3. 

 Andrena convexiuscula K., var. fuscata K.; 4. B. sylvarum L. (T.); 5. B. 

 terrester Z. ; 6. B. variabihs Schmiedekn. {T.); 7. Coelioxys aurolimbata Font.; 

 8. C. conoidea ///. ; 9. C. rufocaudata Sm.; 10. Eucera (Macrocera), ahernans 

 BruU.; 11. E. interrupta Baer.; 12. Halictus albipes F. (T.) ; 13. Megachile 

 ericetorum Zir/>. ; 14. M. lefeburei Z^r^. ; 15. M. muraria 7?f/z. 



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



Herm. MuUer (Thuringia), 2 bees, skg. — Apis mellifica Z. 5, and Megachile 



