268 



H. M. WOODCOCK. 



becomes free, and, correlated with this, there is no undulating 

 membrane. These foims are, for the most part, parasites of 

 Insects which do not suck blood. A stage in advance is seen 

 in H. subulata (fig. 38 e, p), parasitic in the digestive tube 

 of Tabanus glaucopis and Hasmatopota italica, which 

 are predatory on cattle and horses. This parasite, when in 

 the Monadine form, has still the usual acicular shape. The 

 kiuetonucleus, however, lies much farther from the anterior 



Fig. 38. — a, c, Herpetomonas (Critliidia) minuta, 

 Leger; D, attached (giegariniform) stages of sarae ; b, H. 

 gracilis, Leg.; E, r, H. subulata, Leg. ; G, attached stages of 

 same. (All after Leger, X 1800.) 



end, and may, in fact, be almost opposite the trophonucleus. 

 The flagellum, which has been, as it were, drawn back with 

 it, is, in the majority of individuals, attached, for the proximal 

 part of its length, to the anterior part of the body by means 

 of a delicate cytoplasmic border, which constitutes a rudi- 

 mentary undulating membrane. The flagellum, it will be seen, 

 has its root in a diplosome (probably of centrosomic nature) 

 just in front of the kiuetonucleus. 



H. (Critliidia) minuta, Leger, parasitic in Tabanus 

 tergestinus, differs from the last-mentioned type in having 

 the posterior end thicker and more rounded (fig. 36 a and c); 



