86 THE EEPORT OF THE No. 36 



At the College over one thousand kinds of material were examined and almost 

 all were found to contain one or more species of mite, in some cases as many as 

 twelve different species were procured from a sins^le substance. To give some idea 

 of the kinds of materials tested, we might mention the following: manure, moss, 

 deca3dng vegetables and leaves, dead and living animals, herbaceous plants, bark 

 anil leaves of trees, tubers, bulbs and roots, bone, stone, nests of birds and mam- 

 mals, soil, pine and spruce cones, ensilage, fleshy fungi, all kinds of grocery com- 

 modities, clothing, fruits of all kinds, and sawdust. 



Some of the living mites obtained from the mite machines were transferred to 

 pure cultures in order to study their habits and life history. It was found that on 

 proper media it was possible to keep them alive through several generations. Some 

 of the media used are as follows : — First, for living animals — mosquito pupa 

 extract and beef peptone. For living plants — extract of the same plant and on the 

 living host plant. The extract of the plant was made by using two parts by weight 

 of water to one of plant material, and the two heated one hour in a sterilizer and 

 filtered. For mites living on dead matter, the cultures were made in three ways, 

 first, for mites living in nitrogenous substances the culture consisted of whey-pep- 

 tone, whey 80 per cent., agar 10 per cent., and gelatin 10 per cent. Two other cul- 

 tures for the nitrogenous feeders were cheese extract and beef extract. On sacch- 

 arine and acid fruits the media consisted of apple juice. On vegetable matter a 

 culture of potatoes and potato extract gave best results. 



The gratitude of the writer cannot be too strongly expressed to Mr. Nathan 

 Banks, Acarologist of the Bureau of Entomology, Washington, for his able and 

 ready assistance in identifying a large number of species sent to him, and to 

 Messrs. W. E. Thompson, B. Barlow, George Chadwick, Geological Hall, Albany, 

 N'.Y., and Dr. Bethune, for assistance rendered in various ways. 



I.— HABITS OF THE CLASS ACARINA AS AGENTS IN THE TRANS- 

 MISSION OF DISEASE. 



Spread of Bacterial and Fungous Diseases. 



In pathological and bacteriological laboratories, mites are a great nuisance by 

 inoculating pure cultures. Four species were found at the Ontario Agricultural 

 College, — Tyroglyphus Americanus and T. longior feeding upon non-nitrogenous 

 media, and Cheyletes clavispinus and C. longipes feeding on nitrogenous cultures. 

 They make their home in the incubators, and gain entrance to the pure cultures 

 through the cotton wool in the test tubes and between the fittings of the Petri 

 dishes, ^he spores of bacteria and moulds attached to the appendages of the mites 

 are left behind in the pure cultures, where they multiply rapidly and cause no end 

 of trouble. 



The spread of bacteria and moulds in root houses is not duly appreciated. 

 More than a dozen species have been found at Guelph inhabiting turnips, beets, 

 carrots, mangels, parsnips, potatoes, spreading spores of affected roots to healthy 

 ones. Especially noticed in cellars of this kind are Galumna moesta, Rhizoglphus 

 phylloxerae and G. depressa on turnips; Orihatta depressa and T longior on 

 mangels and turnips, and Gamasus species on sugar beets and on parsnips, pota- 

 toes, celery, etc. On fruit trees the spread of brown rot, cankers, pear blight, etc., 

 are carried to a large extent by such species as Tetranychus telarius, T. hicolor, 

 Bryobia pi-atensis, Orihatella pallida, and 0. formosa. 



