ROBERTSON FLOWERS .t INSECTS, ASCL. TO SCROPH. • 5S5 



Linaria vulgaris Mill.* ("Nat. from Eu.") — That the flower 

 is adapted to long-tongued bees is not only indicated by the size 

 of the tube and the length of the spur, but by the fact that only 

 the larger bees are able to open the flower with ease. I have 

 seen a large bee, Botnbus amei-lcafiorum^ visit 62 flowers in five 

 minutes. When a bumble-bee alights upon the palate, its weight 

 opens the flower, and all it has to do is to enter. But the other 

 bees observed by me are not heavy enough to open the flower by 

 their own weight, and so can only enter by squeezing in between 

 the lips. Thus, I have seen the hive-bee enter so as to strike the 

 stamens with its ventral surface or with its side, although it often 

 brings its back against them. Megachile brevis $ goes into the 

 flower upside down, but she may do so intentionally, so as to 

 bring her ventral scopa in contact with the anthers, as she is in 

 the habit of doing on many flowers which are adapted to dust 

 their visitors upon the back. 



Miiller observed bees only on the flowers, but I have seen 

 four butterflies stealing honey. They insert their thin probosci- 

 des between the closed lips with very little chance of touching 

 the anthers or stigma. In the next species the tube is so con- 

 tracted that butterflies can be utilized for transferring pollen. 

 I regard all of the visitors of L. vulgaris as intruders, except 

 IBojnbus. 



On 8 days, between June 25 and Oct. 10, I observed the fol- 

 lowing visitors : 



Hjmenoptera. — A-pida^ (i) Apis mellifica L. ^ , s. & c.p. ; (2) Bom- 

 bus vagans'Sm. ^, s.; (3) B. americanorum F. ,^' 9 ? 5 s. &c.p., ab. ; 

 (4) B. virginicus Oliv. ^ , s. & c.p., one; (5) Megachile brevis Say 9? 

 c.p.; (6) Alcidamea producta Cr. 9> s. and sometimes c.p., when it re- 

 verses to bring ventral scopa against anthers. A7idrenid(M, (7) Agapo- 

 stemon nigricornis F. ^j s., one. 



Lepidoptera. — Kkopalocera, (8) Pyrameis cardui L. ; (9) Pieris rapjE 

 L. : (10) Colias philodice Godt. ; (11) Pamphila cernes Bd.-Lec. — alls. 



Linaria Canadensis Spreng. — I have given some account of 

 this plant, comparing it with other species of the genus, j The 

 tubular portion of the corolla is contracted so that bees cannot 

 enter as in L. vulgaris^ and the nectar is thus comparatively 



* See Miiller. Fertilization of Flowers, 431. f Bot. Gazette, xiii. 12%. 



