142 THE AMERICAN NATURALIST. [Vol. XXXVIII 



In the female of Lampyris noctiluca and the female and larva 

 of Lampyiis splendidula Wielowiejski found a somewhat dif- 

 ferent condition than in the adult male of L. splendid?/ la. The 

 tracheoles arising from the ends of the finer tracheae are gen- 

 erally only two in number. They may also occur along the 

 course of the smaller tracheae, instead of only at the ends, and 

 they may even arise from some of the larger tracheal branches. 

 It is obvious that under such conditions "end-cells" like those 

 figured for L. splendidida would not be present. He states, 

 however, that there is a membrane spread out between the 

 tracheoles, although it fails to give the characteristic " end- 

 cell" reduction with osmic acid. From the larva of L. noc- 

 tiluca he figures one of the larger tracheae with its branches, 

 with a strongly developed, nucleated membrane surrounding it 

 much as a cyUnder surrounds the tracheal axis in the imago of 

 Photinus. The epithelium of the large primary trunks of the 

 tracheae in the larva shows the power of precipitating osmic acid. 



Wielowiejski also studied tracheal endings in other parts of 

 the adult L. splendidula. In the fat body and reproductive 

 organs he found " end-cells " in abundance, similar to the typical 

 ones of the light-organs in their reaction with osmic acid, but 

 differing considerably in shape and in the number of tracheoles 

 contained. In all these instances Wielowiejski interprets the 

 " end-cells " as being a special development of the epithelium of 

 the trachea. In his figures the tracheae, before entering the 

 photogenic tissue, show well developed epithelium, this layer 

 being sometimes almost as thick as the diameter of the tube. 



Wielowiejski neither figures nor describes cylinders in the 

 light-organs of Lampyris. After his study of Luciola itahca 

 ('86) he states that he found no such regular arrangement of the 

 tracheae here as occurs in the tw^o species of Lampyris formerly 

 studied. He did not consider the mass of the cylinders m 

 Luciola as homologous with the "end-cells" of Lampyris. 



In Luciola italica Emery found the ventral layer composed of 

 cylinders and intermediate areas of parenchyma much as has 

 been already described for Photinus. In osmic acid preparations 

 he saw, just within the periphery of the cylinder, small, irregular, 

 three-cornered masses, in which the distal ends of the trachete 



