100 IOWA ACADEMY OF SCIENCES. 



Sphegidae: Ctabro sp. Ammophila conditor. Ichneumonidae : Tryphon sp. 

 Lana montana {?) Coleoptera Meloidae: Epicauta Pennsyhanica feeding on 

 pollen. Hemiptera — Phymata Wolfii. Diptera — Muscidae: Stotnoxys. Meso- 

 grapta marginctta. 



Cnicus altinslmus. Willd. Var. discolor. Gray. Visitors. Hymenoptera — 

 Apidae: Bomhiis fervidus, B. Americamis, B.vaqans. Megachile centuncularis 

 Apis mellifica, Ceratina dupla, Melissodes himaculata, 



MISCELLANEOUS PLANTS. 



Pohjgonum acre. H. B. K. Small spiked flowers. Insects are attracted by 

 its pinkish color. Flowers perfect. 



Visitors — Diptera — Muscidae: Calliphora voniitoria. Hymenoptera — 

 Apidae; Halictus tegularis. Calliopsis andreniformis, Pimpla inquisitor. 

 Sphegidae; Ammophila conditor. Hymenoptera feed on honey secreted at the 

 base of the corolla, while Diptera feed on both nectar and pollen. 



Sediim Telephium, L. Flowers — compound cymes; petals white. 



Visitors — Hymenoptera— ^p/rfae ; Halictus tegularis, Sphegidw; Ammophila 

 conditor, 



Ponfederia cordata L. Blue; spike dense, from a spathe-like bract. Perianth 

 funnel form; two-lipped, three upper divisions united to form the three-lobed 

 upper lip; the three lower ones spreading. The upper lobe of perianth is marked 

 by a pair of yellow spots, which aid the insect in finding the nectar. Stamens six, 

 the three anterior long, exserted; the posterior thrw with very short filaments 

 unequally inserted lower down. Anthers versatile, oval and blue. Pistil one, with 

 stigma turned upward. 



Visitor — Hymenoptera — Apidae: Halictus tegularis feeding on nectar. 



OBSERVATIONS ON THE POLLINATION OF SOME OF THE COMPOSITE. 



BY MARY ALICE NICHOLS. 



The brilliant appearance of our western roadsides and prairies from July to 

 October, invites an extended study of the anatomy and physiology of the Com- 

 positce. The wide distribution and rapid increase of this family naturally call 

 attention to dissemination and pollination. Darwin, Herman Mueller, and others, 

 have shown at length, the direct relation between special adaptations for cross- 

 pollination and the race stability of plants. The question now arises, what are the 

 opportunities for cross-pollination in Compositae, and to what extent is this agent a 

 factor on the increase and distribution of the family? No attempt is here made 

 to go into a discussion in full of these questions for the entire Family, but simply 

 to present a few facts relative thereto, gathered from representatives of the sub- 

 tribes Heliautheae and Asterineae. 



A few observations on the common cultivated sunflower, Helianthus annuiis, 

 will apply equally well to all members of this conspicuous genus. First among 

 these may be noted the mechanism of flowering. Immediately following the 



