646 J. S. DUNKERLY. 



I will first describe the forms met with ])y me in Homa- 

 loniyia canicularis, and afterwards discuss tlieir signi- 

 ficance. (1) In the midgut (ventriculus) of two flies were 

 seen some large typical Herpetomonas forms (PL 31, fig. 1). 

 This form had a body 25 fx to 30 /.t long, and the flagellum was 

 30 ju long. Its movements were characteristic, the body being 

 clumsily swung from side to side by the lashing of the long 

 thick flagellum. With Giemsa's stain the double character 

 of the flagellum described by Prowazek is evident in most 

 cases. If, as Patton (17) states, this is merely a stage in 

 division, then it is an unusual type of division, since the 

 kinetonucleus is not even transversely elongated when the 

 flagellum has divided along its whole length, this being very 

 unlike the state of affairs found by me in dividing forms 

 (PI. 3], fig. 9). My material for the study of these forms 

 has been very scanty, and I can only say that they are very 

 different, both in appearance and size, from the other flagel- 

 lates met with in the fly. 



(2) A commoner form (PI. 31, figs. 2-14) was found in 

 the intestine, and once in the Malpighian tubules. These 

 infections were always heavy ones, the parasites occurring in 

 dense clusters, either on the intestinal wall or free in the 

 lumen of the intestine. On slides the clusters were seen to 

 be formed by the typical rosettes, or more correctly, agglo- 

 merations, with the flagella pointing to the centre, as described 

 by Woodcock (26) for cultural forms of trypanosomes. The 

 body of this form was 15^ to 18^ long, and its movement 

 was rapid and graceful, the anterior part of the body often 

 undulating. A large number of dividing forms were usually 

 present (PI. 31, figs. 6-10). In one case, in which the 

 forms were particularly elongated (PI. 31, fig. 14), cysts 

 were also found, and doubtful intermediate stumpy forms. 

 The characters to which I wish to draw particuhir attention 

 are the varying position of the kinetonucleus and the presence 

 of an undulating membrane (PI. 31, figs. 3, 4, and 11-14). 

 (The forms shown in figs. 3, 4, and 11 are from the same fly). 

 All intermediate stages between the short form, with its 



