191131 Kofoid-McCiiUoch : Trupatiosoma iriaiainar 115 



the parabasal body anteriorly to a position in front of the nucleus. 

 In this crithidial stage binary fission occurs and the flagellates be- 

 come eitlier stout haptomonads attached by their flagella to the surface 

 of the rectal epithelium, or slender motile nectomonads which swim 

 about freely and may re-enter the pylorus, where they apparently 

 may give rise to haptomonads, to rounded-up forms (latent bodies?), 

 or to the terminal little trypaniform stages which pass out through 

 the rectum. As in the pylorus, so also in the rectum, the termination 

 of the process appears to be the small trypaniform stage, though 

 here, too, the small rounded-up form is also found. No stages of 

 sexual reproduction have been detected by these authors at any stage. 

 The material of Trypanusoma triatomae at our disposal does not 

 enable us to outline its full life-history in the bug, but such stages 

 as we find appear to fit admirably into the scheme of development as 

 determined by Minchin and Thomson (1915) in the flea. We will 

 now proceed with a brief account of these and a comparison of them 

 with tlie corresponding phases of T. leivisi. 



Trypanosoma triatomae sp. nov. 

 II. The Trypanosome Ph.\se 

 1. Tin Kirlji stomach phase. — There was but a single bug in our 

 material which had recently fed. Its stomach contained a mass of 

 half-digested blood swarming with trypanosomes of large size (pi. 14, 

 figs. 1-8). In these stages the body is 20-30/x in length and 2-3/* in 

 width. The body has about two undulations, the posterior one occu- 

 pying more than two-thirds of the total length. The anterior 0.2 of 

 the body tapers abi'uptly into the short flagellum, which is also less 

 than 0.2 of the body in length. The nucleus is 3-6^ in length and 

 0.6-1.6;a in diameter. It lies characteristically at one side against the 

 concave surface a little behind the middle of the body. It is dif- 

 fusely granular in our one lot of material of this stage. The flagellum 

 continues as a chromatic marginal thread posteriorly along the convex 

 side of the body to the parabasal body, with which it appears to merge 

 in most cases. The blepharoplast is everywhere small in this species 

 and may be found on closest inspection as a small granule at the base 

 of the flagellum (pi. l-l, figs. 6, 7). From it there runs toward the 

 parabasal body in some instances (fig. 6) a fan-shaped suspensory 

 body or parabasal rhizoplast. In a number of instances of Giemsa- 

 stained individuals a chromatic thread could be traced posterior to 



