3 00 
The Ohio Naturalist. 
[Vol. XI, No. 5, 
The adults are found about flowers or resting on plants near 
the water, and may be collected by sweeping with the net. The 
flowers of milkweed ( Asclepias ) are very attractive to many kinds 
of flies including Stratiomyidae, Syrphidae, Tabanidae, 
Muscidae, Tachinidae, Sarcophagidae, Dexidae and Conopidae. 
Two species of milkweeds are found at Cedar Point, Asclepias 
syriaca L. and A. incarnata L. Along the point in the vicinity of 
Black Channel there is an abundant growth of the former, and at 
times the clusters of flowers are nearly covered with flies and 
many more are buzzing around them. The flowers of this genus 
have a remarkable adaptation for cross pollination by insects. 
As the insect crawls over the flower its claws catch in V-shaped 
fissures between the nectariferous hoods and are guided along a 
slit to a notched disk which clings to the foot. To this disk are 
fastened two flat, spatulate pollen masses or pollinia, which are 
pulled out by the insect and carried to other flowers. A few of 
the small bees and many of the flies are unable to pull out some of 
the pollinia and are thus entrapped. This facilitates matters for 
the collector, for they can then be picked off with the fingers and 
put into the cyanide bottle. Some of the specimens had as many 
as ten pairs of pollinia clinging to their feet. The species of 
Odontomyia are more often entrapped than Stratiomvia, which 
are larger. Those that are not entrapped may often be caught by 
clapping them into the bottle with the cork. The swamp milk- 
weed (A. incarnata L.) is found at the waters edge or at the edge 
of the cat-tail zone. It is not so much frequented by Stratio- 
myidae as by other insects, and on many of the flower clusters 
there are one or two ambush bugs ( Phymata erosa L.), which 
probably devour many of the entrapped flies. 
The yellow pond lily ( Nymphaea advena Ait.) is another flower 
on which a number of flies can be found. They must be approached 
carefully in a boat, for some of the larger flies will fly out if the 
water is much disturbed. On coming near enough one can slip 
the hand under the flower and close it up. The whole flower can 
then be broken off and put in the cyanide bottle for a short time, 
after which it should be removed and the flies sorted out. Other 
common plants which are very attractive to flies and other insects 
are the blue vervain ( Verbena hastata L.), the swamp rose mallow 
(Hibiscus Mosclientos L.) and the pickerel-weed ( Pontederia cor- 
data L.) Good collecting can be done by sweeping among the 
swamp grasses. At times the end of the net, with whatever it may 
contain, can be put in the cyanide bottle for about a minute and 
then removed and the desirable specimens taken out. 
