

312 



BOTANICAL GAZETTE 



[APRIL 



case of the Ichneumonidae only 2 . 5 per cent of the visits are to 



non-social flowers. 



The only flowers supposed to have been modified by the Vespi- 

 dae are the so-called wasp flowers, Epi partis latifolia (Orchidaceae) 



group of non-social 



belonging to the most highly specialized 

 monocotyledons, Scrophularia nodosa (Scrophulariaceae) belonging 

 to a distinctly melittophilous family, Lonicera alpigena belong- 

 ing to a melittophilous genus, and Symphoricarpos racemosus 

 belonging to the epigynous Caprifoliaceae. None of these belong 

 to primitive forms of flowers which might have preceded the 

 advent of the bees. Only 8 . 7 per cent of the visits of Vespidae 

 are to non-social flowers. 



With the exception of Symphoricarpos, all of the flowers men- 

 tioned by Muller as having been modified in adaptation to the 

 lower Hymenoptera are zygomorphous : Orchidaceae, Papilionaceae, 

 Labiatae, Scrophularia, and Lonicera alpigena. Zygomorphous 

 flowers, except such forms as Aristolochia, with siphonate zygo- 

 morphy, and the outer flowers of the umbels of Heracleum, with 

 radiate zygomorphy, are typically non-social and adapted to bees 

 which visit each flower separately. They have a landing either 

 above or below the stamens and pistils and usually dust the visitor 

 on the lower or upper side. It is fairly inconceivable that zygo- 

 morphy should have originated in crowded inflorescences where 

 the flowers might be approached from any side. Excluding such 

 flowers as Heracleum, Aristolochia; Amorpha, Petalostemon, and 

 Melilotus in Papilionaceae ; and Pycnanthemum, Lycopas, and 

 Mentha in Labiatae, 100 zygomorphous flowers show: bees 74-3* 

 Diptera 8.5, other Hymenoptera 9.1, Lepidoptera 7.1, Coleoptera 

 and Hemiptera 0.7, making a total of 1 1 1 7 visits. 



Visits to the Papilionaceae show: 



' 



Non-social (24) . . 



Social (9) 



Total (33) 



Amorpha, etc. (4) 



Bees 



Diptera 



Other 

 Hymen- 

 optera 



Lepidop- 

 tera 



Coleop- 

 tera. He- 

 miptera 



- 



975 



1.6 



0.8 



O.O 



O.O 



56.1 



16.3 



23.0 



*5 



2.9 



65.0 



1 S 1 



18.2 



1.2 



2.2 



45 3 



18.5 



29.4 



2-3 



43 



Total 



123 



447 

 570 

 3° 2 



