91 



upon it. The nectar is secreted by the fleshy disc below the 

 ovary and is protected from unbidden guests by small pro- 

 jections. Mr. Robertson, in speaking of the flower, says. 



"The tubes measure 18 to 19 ram., which indicates an 

 adaptation to long tongues. The form of the tube, the bil- 

 abiate corolla, and the position of the stamens and style indi- 

 cate that the flower is a modification of a nototribe flower 

 originally adapted to bumble-bees. The level-topped heads, 

 the erect corollas, the exposed organs and the rose color in- 

 dicate a tendency to suit butterflies, which in fact are the 

 principal guests." 



Among the insect visitors here at Ames are: Hymenop- 

 tera Bombus virginicus, B, pennsylvanicus, Odytierus 

 foraminatus and Lasivs hrunneus; Diptera, two species 

 of the family Bomyplidae; Hemiptera, Phymatus wolfii, 

 Lygus pratensis, and Galcoris rapidus. In Colorado it is 

 much visited by several species of the Genus Bomhus, 

 also some Lepidoptera- In Wyoming where I observed 

 this species this sumnier Bombus is also a frequent visitor. 

 The flowers have a much deeper color especially at an atti- 

 tude of 5000 feet. 



Lamium amplexicaule L. Species of the genus 

 Lamium are adapted to bumble-bees. Mueller never suc- 

 ceeded in finding bees in the species here considered. He 

 says; "But I have found immediately after the opening of 

 the flower, the tip of the lower stigma standing not above 

 but below and between the anthers, and dusted with pollen, 

 no doubt from the same flower." The purpose of calling 

 attention to the species here is that the plant has in addition 

 to the ordinary' also clesistogamous flowers. Axell was of 

 the opinion that the existence of such flowers in this species 

 was due to a lower tempature which checked the develop- 



