Biology Commons^™

A Contribution To Our Knowledge Of The Aphididae Of Utah, George Knowlton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There are many groups of insects in Utah that have not been touched in a systematic way up to the present time, and to the knowledge of the author no systematic work has been done on the homopterous family Aphididae.

Due to the very common occurrence of the aphids, or plant lice, and the need for a simple key that would aid in the determination of these insects, this work was commenced in June 1923, continuous work being carried on in collecting, determining, drawing and describing, up to the present time.

Critique Of Influence Of Mineral Manures Upon The Mineral And Nitrogen Composition Of Plants, Dan Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Variation in quality of plants of the same species has been known to exist for a long time. The influences bringing about such variation have been studied only comparatively recently. Quantity production has been given the greatest amount of attention as a rule, the beneficial results from the use of manures being judged by the quantity of produce. Some plants, however, varied so widely in composition, and the variations were of such paramount importance, that the influences affecting quality began to receive some attention. Of this type of plants may be mentioned sugar-beets and tobacco. There was also the hope …