3°° 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 (Asdcpias) are very attractive to many kinds 

 of flies including vStratiomyidae, Syrphidae, Tabanidae, 

 Muscidae, Tachinidae, vSarcophagidae, Dexidae and Conopidae. 

 Two species of milkweeds are found at Cedar Point, Asclepias 

 syriaca L. and .4 . 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, spatiilate 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 

 Odontomjda are more often entrapped than vStratiomyia, 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 vStratio- 

 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 {Xymphaea 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 inallow 

 {Hibiscus Moschentos L.) and the pickerel-weed {Pontederia cor- 

 data L.) Good collecting can be done b}' 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. 



