PLATE XXV 



Figure 1. The hind-gut of Hippobosca macnlata, showing the 

 openings of the four separate Malpighian tubes and 

 the rectal ampulla, v., sphincter muscle at the opening 

 into the ampulla, d.i., distal intestine, mp.t, Malpi- 

 ghian tubes, x 36. 



Figure 2. A transverse section through the posterior part of the 

 abdomen of Haematopota pluvialis. The section from 

 which this was drawn was not cut in an absolutely 

 transverse plane, so that the two sides are not symme- 

 trical, t.m., circular muscle fibres, connecting the 

 tergite and sternite. f.b., fat body, l.m., longitudinal 

 muscle fibres, connecting the adjacent tergites and 

 sternites respectively, h., heart and pericardial cells. 

 ^^^ h.g., hind-gut, cut in three places on account of its 

 twist. ov., ovaries : the several tubules are cut at 

 different levels, some through the nurse cells, the nuclei 

 of which are conspicuous. a.g., accessory glands of 

 the reproductive organs", x 66. 



Figure 3. Cells from the upper part of the mid-gut of PJiilae- 

 matotnyia insignis, a short distance below the pro- 

 ventriculus. x 500. 



Figure 4. Cells from the middle portion of the mid-gut of the 

 same. X 450. 



Figure 5. Longitudinal section through the abdomen of Pliilae- 

 matomyia insignis, to one side of the middle line, 

 ha., haematocoele, always apparently a large space in 

 sections, on account of the unavoidable shrinkage, d.i., 

 portions of the distal intestine cut through obliquely, 

 ch.t., abdominal tergite. r.p., rectal papilla, rt., 

 rectum, c., a mass of cells around the rectum, most 

 of which belong to the proximal ends of the Malpi- 

 ghian tubes, mb., the membraneous portion of the 

 ventral wall, which is only chitinized in the middle line, 

 p.i., proximal intestine, sl.g., salivary glands, ch.v., 

 chylific ventricle, m.ph., mesophragma. pv., proven- 

 triculus. Note the large number of circular muscle 

 bundles, x 69. 



Figure 6. The rectum of Musca, showing the tracheae entering 

 the rectal papillae, x 66. 



