110 The Botanical Gazette. [March, 
of the pollinia of Asclepias, which approximates them, is in- 
tended to facilitate the introduction of both pollinia into the 
same stigmatic chamber. In Cynanchum vincetoxicum,® 
whose mechanism in a general way resembles that of Eus/enza, 
Miller states that the retinacula bend so that the pollinia 
come close together. The flowers are adapted to carrion 
flies, Muscidae, Sarcophagide, etc., and I suspect that the 
movement is merely to turn the knees away from the pro- 
boscis. Miiller’s account of the pollination of Cynanchum 
seems to me to be just as erroneous as that of Ascleptas 
Cornuti. In tbe normal pollination of any asclepiad I doubt 
if it can be shown either that the part to which the corpus- 
culum is attached is again caught by the wings, that the cor- 
pusculum ever enters the slit, or that both pollinia together 
are ever introduced into the same stigmatic chamber. 
The flowers of Enslenia are visited principally by bees of 
the genus Halictus. These insects readily remove the cor- 
puscula, which are found attached to the palpi, the tips of 
the lamine, or other fine divisions of the proboscis. Myzine 
sexcincta was abundant on the flowers, but I could find no 
examples bearing corpuscula. The following list was taken 
on July 14th, 20th, and August 22d; the insects bearing cor- 
puscula are indicated by ! 
.» ab, 
Diptera—Empide: (12) Empis clausa Rob. MS; Bombylide: (13) 
Anthrax fulvohirta Wd., ! 
Carlinville, Ills. 
®Miiller, Alpenblumen, 350. Fertilization of Flowers, 401. 
