644 H. M. WOODCOCK. 



blackbird caught for me at Elstree, which died two days 

 after receiving it. Neither in this, nor in another blarkbird, 

 purchased, were any trypanosomes found. A barn-owl 

 (Strix flammea), which was kindly given me by Dr. Dean, 

 also proved negative.^ I may add here that in one of the 

 Paddas and in one blackbird Halteridia occurred, but 

 sparingly ; I thought it best, however, not to take up this 

 aspect of the question at first, but to continue my search 

 for haemoflagellates and concentrate my attention on them 

 in the first place, turning to the Haemosporidia later, as 

 should appear desirable. 



The small birds, of which I have examined most, are 

 closely allied members of the finch family (Fringillidae, 

 sub-fam. Fringillinae), namely, greenfinches (Chloris 

 chloris), chaffinches (Fringilla ccelebs),i-edpolls (Li not a 

 [Acanthis] ruf escens), and linnets (L. [A.] cannabina). 

 Trypanosomes were found only in the chaffinches and red- 

 polls, so that for the greater part of the time I have occupied 

 myself entirely with these. Unfortunately during the spring 

 these birds also were very scarce and difficult to procure, 

 and I was unable to replenish or augment my stock when 

 I particularly wished to do so. 



The occurrence of the parasites in these two hosts cannot 

 be considered as at all rare. Out of twenty-two chafiinches 

 examined, five were found to be naturally infected, sixteen 

 birds were certainly uninfected, and one was doubtful. 

 Neglecting this last,- the percentage works out at about 

 24. As regards the redpoles, trypanosomes occurred in 

 three out of fifteen ; eleven were uninfected, and one, again, 

 was uncertain. This gives an approximate percentage of 

 21*5, which is not very different from that in the case of 

 the chaflfinches. As far as they go these proportions are 

 reliable, because they are exhaustive — that is to say, the 



> In the case of blackbirds this was not conclusive as to the absence 

 of the parasites, for no cultures were made (cf . below, p. 658). 



^ Also in the case of the first chaffinch and redpoll no cultures were 

 taken, as I had no tubes ready at the time. 



