No. 446.] 



PHO TINUS .1/. / RCIXEl.L I 



and bases of the tracheoles appeared to l)e inibcddc 

 tracheal axis was isolated these small bodies looked 1 

 on a stem," while from each " grape " two trachcole 

 As these browned bodies were found only in tin- 

 preparations he believed them to be artiiarts, a 

 "tracheal end-cells" of Max Schultze. lie concliK 

 clear cell elements of the cylinder are the real 

 Within these the tracheae undergo their tinal di 

 giving rise to two tracheoles. In Luciola only that 

 cell which is in direct contact with the i)ascs of the 

 blackened by osmic acid. 



Emery agrees with Wielowiejski in considermg th; 

 cells" are formed from the tracheal epithelium. 



Two of the latest investigators of tracheal endin- 

 hausen and Holmgren, have both worked on the s 

 lepidopterous larvse. Both found the finer track 

 over into what they term the " tracheal capillary en- 

 a network formed by the anastomosing of the tra 

 their branches. They agree in stating that the e 

 the tracheoles is extended in a web-like manner ' 

 "end-cells." Holmgren discards the term er 

 stituting for it the 

 more correct name 

 of "transition cells," 

 as these structures 

 form the transition 

 between the tracheal 

 tubes proper and the 

 tracheolar net-work. 



In the light-organs 

 of Photinus, fixed for 

 thirty hours in .1 



osmic acid and . .. 



stained with safra- 



nin, the transition 



cells may be seen 



most plainly. The) 



show with varying j.,,,.; r,,- 



