71 



with remains attached to the hairs. When older, these 

 branches turn back and an insect going to a flower cannot 

 but help get some pollen on its body, and as it goes to an- 

 nother flower it is almost certain to leave some pollen on the 

 stigma. While cross-pollination is almost certain to occur, 

 self-pollination and self-fertilization may also occur. 



Golden-rod. {Sol dago stpeciosa, Nutt). The flowers are 

 yellow, otherwise characters much the same, 



as in yarrow. It is visited by the following insects: 

 Hymenoptera — Apidae: Bombus Virginious, sucking 

 honey Apis melUfica sucking honey (quite abundant.) Halic- 

 tns coriaceus, Augochloro pura, Cilissa Americana, Caliopsis 

 andreniformis. Sphegidae: Crabro sp.. Ammophila condi 

 tor. Ichneumonidae : Trpphon sp. Lana montana ( ? ) 

 optera Meloidae: Epicauta pennsylvanica feed ing'on pollen. 

 Ilemiptera — Phymata wolfii. Diptera — Muscidae: Stom- 

 oxys. Mesograpta marginata. 



Sunflower. The flowers are collected in heads and are 

 made attractive because of the large yellow rays flowers. Like 

 yarrow they are prolerandrous. At Ames they are visited by 

 Lepidoptera — Chryspophanus thoe. Diptera — Bomhylidae: 

 Bombylius- B.ymeuo^tera.— Apidae: Nomada luteola^ 

 gathering honey. HaUctus Leronodi. Mellissodes per- 

 plexa, gathering pollen and sucking honey. Vespidae: 

 Odyneris foraminaUis. 



Bull Ihistle. Bull thistle is common in pastures and 

 is rendered conspicuous because the purple flowers are col- 

 lected in heads. It is strongly proterandrous. In the first 

 stage a large quantity of pollen is pushed out by the style 

 from the opening of the syngenesious anthers. When the 

 style occurs outside of the anther tube a bunch of hairs may 

 be seen as brush hairs. These not only help to take out 



