[C] The water here is probably not more than fifteen degrees above that in which _C. virilis_ was found to be so numb as to be almost incapable of movement. See Harris, Annotated Catalogue. OBSERVATIONS ON THE POLLINATION Of Solanum rostratum Dunal and Cassia chamæcrista L. BY J. ARTHUR HARRIS AND OSCAR M. KUCHS. With Plate I. In 1882 Professor Todd published his interesting observations[D] on the pollination of _Solanum rostratum_ and _Cassia chamæcrista_. Since that time, so far as the writers are aware, nothing has appeared upon this subject. During the months of August and September, 1901, opportunity was afforded the writers for making more extended observations on these species. The notes here given are the result of these observations. In some respects, these observations, or the conclusions drawn from them, differ essentially from those made by Professor Todd; in others they are practically the same. The writers feel that, even where observations or conclusions are the same, the confirmation of Professor Todd’s results is of value, since the data have been collected in a different locality and a different year. It must be borne in mind that the lack of agreement between the observations in the present paper with those made by Professor Todd is probably largely due to the inferior quality of his material. _S. rostratum_ had been but recently introduced into southern Iowa when Professor Todd’s article was written. It apparently did not thrive very well, the greatest number of flowers mentioned as appearing on any one plant being ten—a very small number to be produced by a plant of any considerable size. While also an introduced plant in eastern Kansas, it has been long and well established, and grows luxuriantly.[E] The data upon which the conclusions here given are based have been given largely in tabulated form. For the present purpose, it might have been sufficient to give only the summarized results of some of the tables. They have, however, been inserted in full, since the writers hope that they may be useful in future work on these plants, and since they believe that the collection of carefully prepared statistical data of this kind is very valuable for the decision of some biological questions. The writers wish to express their gratitude to W.C. Stevens, professor of botany, for suggestions on the work, and to Hugo Kahl, entomologist of the University of Kansas, for the identification of the insects. The drawings were made by Miss Marguerite E. Wise. _S. rostratum_ is a low, spreading, bushy annual, sometimes attaining a diameter of four or five feet and a height of one and one-half feet.[F] The pinnately lobed leaves, as well as other parts of the plant, are beset with strong prickles. It seems to be especially adapted to arid regions, thriving on the dry plains of the Southwest.[G]