328 ANCIOSPERMAE—DICOTYLEDONES 



In Dumfriesshire a Muscid and several Dolichopodids were recorded (Scott- 

 Elliot, ' Flora of Dumfriesshire,' p. 48). 



771. V. tetrasperma Moench (=Ervum tetraspermum L.). — The mechanism 

 of the bright yellow flowers of this species is not, according to Kirchner (' Flora 

 V. Stuttgart,' p. 504), so much simplified as in the last species, but essentially agrees 

 with that of V. Cracca. The alae possess the finger-shaped processes overlapping 

 the sexual column, and in front of these there are two outgrowths on either side 

 which fit into and are loosely united with corresponding carinal depressions. The 

 upper margins of the carina lie close together ; the base of the vexillum ensheaths 

 the claws of the other petals. The anthers dehisce just before the bud opens, and 

 some of the pollen falls upon the collecting-brush. 



Visitors. — I observed the honey-bee and Halictus sp., skg., at Kiel (' Bloemen- 

 biol. Bijdragen '). 



772. V. pisiformis L. ( = Ervum pisiforme/'^'/frw;.). — The greenish to yellowish- 

 white flowers of this species were investigated by Herm. Miiller in Thuringia (' Weit. 

 Beob.,' II, pp. 258-60). Their mechanism is intermediate between those of V. 

 sepium and V. Cracca. The style is provided with a very regular brush for almost 

 half its length from the stigma, and the anthers (which dehisce in the bud) deposit 

 the greater part of their pollen upon it. The upper margins of the carina are 

 readily separated, so that when it is depressed the stigma, stylar brush, and all 

 the stamens protrude. Union between carina and alae is effected very much as 

 in V. Cracca and V. sepium. But the finger-shaped processes on the bases of the 

 alar laminae are broader and thicker, triangular in form, and only gradually becoming 

 slender and flattened towards their tips. They consequently cause the return of 

 all the parts of the flower to their original position more efficiently than in the 

 other two species. The vexillum is pressed against the alae by means of two slight 

 folds situated at the junction of its claw and erect lamina, and diverging to the 

 front superiorly. Unbidden guests are thus excluded. Since the claw of the vexillum 

 is 8-10 mm. long, the proboscis of insect visitors must be of the same length. 

 Many shorter-tongued bees, however, are able to thrust their heads under the claw, 

 thus reaching the nectar. 



Visitors. — Herm. Miiller observed the following. — 



A. Hymenoptera. Apidac: i. Bombus lapidarius L. 5, skg.; 2. B. rajellus 

 K. 5 and 5, do.; 3. B. sylvarum L. 5, skg. and po-cltg. ; 4. Halictus tetragonius 

 Klg. 5, po-cltg.; 5. Megachile circumcincta K. 5, skg. and po-cltg.; 6. M. versicolor 

 Sm. 5, do. B. Diptera. Syrphidae : 7. Syrphus balteatus Deg., hovering and vainly 

 skg. C. Lepidoptera. Rhopalocera : 8. Coenonympha arcania L., skg. 



A. Schulz saw flowers perforated by humble-bees. 



773. V. sylvatica L. (=Ervum sylvaticum Pelerm.). — 



Visn ORS. — In Dumfriesshire 2 humble-bees were recorded (Scott-Elliot, ' Flora 

 of Dumfriesshire,' p. 49). Schulz saw flowers perforated by humble-bees. 



774. V. cassubica L. (=:Ervum cassubicum Peterm.). — 

 Visitors. — Schulz saw flowers perforated by humble-bees. 



