194 ANNIE PORTEK. 



The Malpighian tubules of Melophagus ovinus are 

 sometimes invaded by Crithidia melophagia, but this is 

 not common. 



Parasites were more numerous in female than in male keds. 



Repeated investigation of sheep's blood failed to show the 

 presence of any flagellate therein. Flu and Swingle obtained 

 similar results. C. melophagia is, then, purely a parasite 

 of Melophagus ovinus. 



MOVKMEXTS. 



The movements of C. melophagia are very vigorous. 

 The parasites are even more active than C gerridis (see 

 Porter [1909], p. 352). As in C. gerridis, the membrane 

 takes an important share in locomotion, bnt the movements 

 of the body of C. melophagia are not so noticeable as in 

 the parasite of the water-bug. 



When C. melophagia was examined nnder the water 

 immersion (2'5 mm.) objective, the movements of the less 

 active organisms could be analysed. In progression the 

 organism moves with its flagellum foremost, and the latter 

 executes vigorous, slightly spiral, boring movements. The 

 body also aids in pi'ogression, for waves pass from the 

 posterior end towards the flagellum, causing a series of 

 peristaltic-like swellings. The body of the parasite seems to 

 become shorter during this period, and then by i-elaxing to 

 move forwards. The bead-like swellings due to undulatory 

 movements are more noticeable in certain areas, and in the 

 living organism myonemes could be sometimes seen both on 

 the body and in the membrane in these regions. Flu has 

 also figured myonemes on some of the parasites he drew, and 

 observation of them in life confirms his work, but it was with 

 the greatest difficulty that I could find myonemes in stained 

 specimens (PL 12, figs. 17, 18, 40, 42, 45). 



The body of C. melophagia, compared with that of C. 

 gerridis, is relatively rigid, but slight twisting movements do 

 oficur. The previous workers on C. melophagia are agreed 



