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TEXT-BOOK OF ENTOMOLOGY 



ever, that the trachea! endings lie between the cells. Wielowiejski, 1 

 in describing the line tracheae of the phosphorescent organs, thinks 

 that the trachea! endings (trachea! capillaries) rarely end blindly, 

 but anastomose with one another, forming an irregular network. 



a 



FIG. 398. Traeheal net-work of the male glands of Lampyrifi ftplendidula : tec, tracheal end- 

 cells ; cap, tracheal capillaries ; at a, an expanded matrix. After Wielowiejski. 



The latest observer, Gilson (1893), asserts that tracheal twigs pene- 

 trate deeply into the epithelial cells of the silk glands of larval 

 Trichoptera as well as of caterpillars, passing through their proto- 

 plasm. 



FIG. 399. Traeheal capillary end-network (tr. c.n.) of silk glands of Ocneria d inpar : p, 

 peritoueal (peritracheal) membrane. After Wistiiighausen. 



A late investigator, C. von Wistinghausen, finds in the tracheae of the spin- 

 ning-glands of caterpillars a completely formed network between the terminal 

 branches of two or several tracheal groups. The tracheal tubes of this series of 



1 Studien iiber die Lampyriden, Zeits. fiir wiss. Zool., xxxvii, 1882. Both Wielo- 

 wiejski and M. \VistiiiL, r li;iuscii have completely disproved the view of Schultze, that 

 the tracheae end in star-like cells, where respiration takes plaee, as the "star-like 

 cells " are simply net-like expansions of the peritoneal memhraue of the trachea;. 



