f>LATE XXIV 



Figure 1. The alimentary tract of Phil a etn atomy ia insignts. 

 c.v., chylific ventricle, or first part of the mid-gut, 

 p.i., proximal intestine, pv., proventriculus. sp., a 

 thickening- of the circular muscle of the gut wall, 

 probably acting as a sphincter, h.g., hind-gut. Other 

 letters as before, x 12. 



Figure 2. A longitudinal section through the proventriculus of 

 Philaematomyia insignts, showing the origin of the 

 peritrophic membrane, j., the junction of the fore-gut 

 and the mid-gut. oes., the invagination of the 

 oesophagus into the mid-gut, f.g., fore-gut, c., com- 

 mencement of the mid-gut. pt.m., peritrophic 

 membrane. 



Figure 3. Cells from the hind-gut of PJiilaeinatoinyia itisignis, 

 showing the chitinous spines. 



Figure 4. A diagrammatic section through the mid-gut of a Muscid 

 fly to show the peritrophic membrane in situ, m.c., 

 the cavity of the mesenteron. ep., epithelium of 

 digestive cells, pt.m., peritrophic membrane. 



Figure 5. A diagrammatic longitudinal section of the alimentary 

 tract of a Muscid fly, to show the relations of the 

 peritrophic membrane. Lettering as before. This 

 and the last figure after Berlese, slightly modified. 



Figure 6. A portion of the distal end of the Malpighian tube of 

 Philaematomyia insignis. X 150. 



Figure 7. A portion of the proximal end of the same, x 150. 



Figure 8. The alimentary tract of Glossina, in sitti. ph., 

 pharynx. oes., oesophagus, c.cg., the common 

 salivary duct, formed by the union of the two ducts, 

 c.j., duct of the crop, j., the crop, pr., proventriculus. 

 i.th., thoracic portion of Jhe intestine, i.m., abdominal 

 portion, a.r., rectal ampulla, gl.s., salivary glands, 

 r., rectum, or hind-gut, p.r., rectal papillae. From 

 Rouband, after Minchin. 



