778 DR JOHN RENNIE ON 



It is noteworthy that many species occur on plants, but, as has been shown, 

 these, as far as known, do not possess the specialised characters of T. woodi, and for 

 this reason it seems improbable that bees have recently become infected from flower- 

 haunting forms. It is more probable that this took place through contact with 

 other insects, possibly robbing visitors to hives. 



It may be remarked that along with my colleagues I have examined numbers of 

 wasps, humble bees, earwigs, wax moths, Braula cceca, and although other mites 

 were readily found upon the exterior, particularly upon the earwigs, the thoracic 

 tracheae in all cases were found clear. 



The importance of finding answers to all of these questions raised is fully recog- 

 nised by the Investigation I have the honour to direct, and the work is continuing 

 with unabated vigour. I desire to take this opportunity of thanking my colleagues 

 for the skill and ability with which they have aided me in the work so far accom- 

 plished, and particularly Miss Elsie Harvey, my personal assistant, whose loyalty 

 and diligence have been noteworthy. 



The foregoing researches have been carried out under the Joint-Committee upon 



Animal Nutrition of the University of Aberdeen and the North of Scotland College 



of Agriculture, with the aid of grants from the Development Commission, together 



with the generous financial help of A. H. E. Wood, Esq., of Glassel. To all of these, 



for their valuable assistance, and to the Local Advisory Committee, under Professor 



John Arthtjr Thomson, whose encouraging advice has been unfailing throughout, 



I desire to express the cordial thanks of my colleagues and myself. I also desire to 



thank the Carnegie Trust for help in connection with this research. 



Pakasitology Laboratory, 

 University op Aberdeen. 



REFERENCES. 



Banks, Nathan (190i), "A Treatise on the Acarina or Mites," Proc. N. S. Nat. Mus., Washington, xxxiii, 



No. 1382. 

 Bbblesb, a. (1897), Acari, Myriopoda, et Scorpiones huiusque in I/alia reperta. 

 Blanc et Rollbt (1910), " De la presence chez THomme de Tarsonemus hominis Dahl," Compt. Rend, de la 



Soc. de Biol, t. Ixi.x, p. 333. 

 Canestrini, G. (1888), Prospetto dele Acarofauna Italiana, Padova. 

 Dahl, Fr. (1910), "Milben als Erzenger von Zellwucherungen," Centralb. f. Bakt. u. Parasitenk, Bd. liii, 



Grig. p. 524. 

 Myake and Soriba (1893), " Vorl. Mitth. iiber ein. neuen Paras, d. Mensch," Berl. klin. Wochenschr., xvi 



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 OuDEMANS (1906), Entomologische Berichien, v. 4, Nos. 91 and 92, p. 316 and^p. 331. 

 Rbutbr, E. (1910), Centralb./. Bakt. u. Parasitenk, Bd. Ivi, Grig. p. 339. 

 Saul, E. (1913), Centralb./. Bakt. u. Parasitenk, Bd. Ixxi, Grig. p. 59. 

 Trouessart, E. (1892), "Considerations generales sur la classification des Acariens,'' Revue SH Nat de 



r Guest, Paris, p. 20. 

 Zander, E. (1911), Krankheiten uiid Schddlinge der erwachsenen Bieneii, Stuttgart. 



