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Flowers and Insects, AscIepiadaceR' to Scroj'^hnla- 



riacew. 



By Charles Robertson. 



Presented Feb 2d, 1S91. 



The following paper belongs with a series of papers begun in 

 the Botanical Gazette in May, 18S9, and giving an account of 

 observations made at Carlinville, 111., in 1866 and following 

 years. The paper on "Umbelliferre," in the fifth volume of these 

 Transactions, pp. 449-460, belongs with the same series. 



A bibliography of the literature of the fertilization of flowers 

 by D'Arcy W. Thompson will be found in Hermann Miiller's 

 " Fertilization of Flowers," 599-634. This list includes works 

 published up to 1SS3. A continuation of this bibliography up 

 to 1SS9, by J. McLeod, will be found in the Botanisch Jaarboek, 

 Gent, Tweede Jaargang, 1S90 



ASCLEPIADACE^. 



In the Botanical Gazette, vol. xii., 207-216, 244-250, I have 

 given an account of the following species of Asclepiadacecc. I 

 shall now add a list of visitors of each of them. The name of each 

 insect is followed by c, h.,t., p., or sp., according as the corpus- 

 cula were found attached to the claws, hairs of the legs, tongue, 

 pulvilli, or spurs of the tibiie. In most cases, however, the pul- 

 villi and spurs are counted as hairs and marked " h." 



Asclepias verticillata, L. — On 15 days, between July 11 and 

 Aug. 21, I observed the following visitors: 



Hymenoptera — Apidce. (i) Apis mellifica L. $< , h. ; (2) Bombus sepa- 

 ratus Cr. "J, 9 5 , h. ; (3) B. virginicus Oliv. § h. ; (4) B. americanorum F. 

 ^ ; (5) Apathus laboriosus F. 9; l^- ; (6) Melissodes bimaculata Lep. 

 ^9 h.t.; (7) Ceratina dupla Say 9,h.c.p.; (8) Megachile brevis Say 

 ^ 9. h.t.; (9) Heriades carinatum Cr., 9 P-? (10) Coelioxys 8-dentata 

 Say "J,, h.; (11) Epeolus lunatus Say %. h. AndrefiidcE, (12) Halictus 

 lerouxii Lep. % 9, h.c.t. ; (13) H. fasciatus Nyl. -J, 9 . h. (14) H. con- 

 fusus Sm. 9> P-i (15) ^' stultus Cr. $ ; (16) H. albipennis Rob. -J, ; 



