102 IOWA ACADEMY OF SCIENCES. 



the bees just described, and Diabrotica lonfficontis, whose proboscis and antennae 

 were frequently found sticky with nectar or resin, to which numerous pollen grains 

 adhered. 



On Helianthns grosse serratus Martens, a very showy species which flowers in 

 September and forms corymb like clusters, the following were found: Diabrotica 

 longicornis, Bombylini, whose downy body and barbed proboscis were admirably 

 adapted for transportation of pollen, and Morclellestina comnta, a small brown beetle 

 found in great numbers buried deep in the disk both before and after the open- 

 ing of the disk flowers. The legs and antennae are slightly downy and in some 

 cases adherent pollen occurs. 



On H. rigidus the common visitors were Bombylini, Bombus, and Apis mellifica. 

 In addition to these, Hermann Mueller gives for H. multiflorae: Megachile cent- 

 HHCularia, Halictus zonulus, Eristalis tenax, Syrphus pyrastie, and Syrphus 

 ribesii. 



On H. laetiflorus Pers. were found Bombus Pennsyhnnicus, and Diabrotica 

 longicornis. On this, as on several other members of the genus, grasshoppers fre- 

 quently appeared. They were very destructive, to the ray flowers, but apparently 

 played no part in the process of pollination. 



The genera Lepachys and Rudbeckia stand so close, structurally, to Helani- 

 thiis, as to need no special description. 



On Lepachys pinnata Torr. and Gr., MelUsodes obliqiuis and Phymata tvoljii, 

 were found. 



On Rudbeckia hirta and R. triloba, the only common visitor observed was Phy- 

 mata ivolfii. Since these are abundant and widely distributed species, and since 

 this insect is one of slow movement; and, moreover, one on which no pollen was 

 at any time detected, it seems reasonable to conclude the species of this genus are 

 largely self- pollinating; R. subtomentosa, however, being sweet-scented, is fre- 

 quently visited by bees {Apis mellifica). 



In smaller heads, but scarcely less showy than the Helianthoide<e, is the extensive 

 genus Solidago, of the Asteroidece. The flowering mechanism of Solidago and 

 Helianthns are practically the same, except that in Solidago the anther tube, 

 remains protruded for some time before dehiscence, and in the meantime the cor- 

 olla fades. Hence the most showy period of the flower's existence occurs before 

 the maturity of either stigma or anther. Its less attractive appearance is, per- 

 haps, overbalanced by the distinct odor which ueems intensified by the beginning 

 of the process of decay. 



Insects were observed on the following species: Solidago speciosa and S. Inn' 

 ceolata. The frequent visitors were Acinandero piilchella, Ammophila, and Epi- 

 caiita pennsylvanica. Of these, the la,st named is so common as to be intimately 

 associated with the flower in the minds of the most casual observers. It appears 

 usually, soon after the deshiscence of the anther — occasionally before — and plies 

 industriously from flower to flower, apparently finding uectar at the base of the 

 pistil, and industriously bearing pollen from floret to floret, and from head to head. 



Ammophila flits very rapidly, alighting but for an instant here and there, and 

 attbrdmg no opportunity for observations on its motives or operations. 



On other species, Mueller furnishes the following more complete lists: 



On Solidago Canadensis . — Eristalis arbiistoriivi E. nemornm. Syritta pi2)iens* 

 Sarcophaga carnaria, and numerous small Muscidae. On SoUdaqo virga-aurea 

 (L.):- 



Ap s mellifica, Bombus rupestris, B. campestris, B terrestris, Andrena denti- 

 culata, Eristalis arbustorum, E. nemorum and Thecla ilicis. 



