6 Illinois State Lahora.tory of Natural History. 



and now takes the form of rows of short, transverse coe- 

 cal tubules, standing- in general at right angles to the 

 small intestine, but with their inner ends the smaller. 

 They are fused into a continuous layer, and make by 

 their arrangement a broad plaited border on each side 

 of the intestine for its whole length, from the stomach 

 to a bladder-like expansion into which the Malpighian 

 organs open. A large trachea runs along the intestine, 

 and its branches are very liberally distributed, right and 

 left, to all parts of these gland-like bodies*. The tubules 

 are lined with a single-layered epithelium very different 

 from that of the part of the intestine into which they 

 open. They may be easily demonstrated, by pressure 

 under the microscope, to open separately into the ali- 

 mentary canal running along between the rows, and the 

 same fact is evident in stained sections. In ever^'^ case, 

 again, the intercellular substance within these tubules 

 is little more than a mass of bacteria, — micrococci ,or 

 bacilli, as far as determined. 



The same may be said of the Pentatomidap and Cori- 

 melsenidse dissected, — Corimelsena, Peribalus, Morm.idea, 

 Eusehistus, and Hymenarcys, — except that in these fami- 

 lies there are always four rows of the short transverse 

 tubules instead of two. In Capsidae. Nabidre, Reduviidse, 

 and Aradidif— the only other families examined with this 

 matter in mind — we have not found these structures, and 

 Dufour notes their absence in examples of these families, 

 and in Mii'is, Phymata, Cimex (Aeanthia), and the lower 

 Hemiptera generally. 



In every case where they have occurred in our dissec- 

 tions, we have made exhaustive search for bacteria in 

 other parts of the alimentary- canal also, and in the sal- 

 ivary glands, the fatty bodies, etc., and in all these 

 Hemiptera with only negative results. 



* The abuii'lant trai^heal supply of these organs and the minuto distribu- 

 tion of the tracheal branohos— scarcely less abundant than iu the fatty bodies, 

 and much more so than in other portions of the alimentary canal— hint at a 

 peculiar function for this so-called pancreatic apparatus. 



