436 



TEXT-BOOK OF ENTOMOLOGY 



ever, that the tracheal endings lie between the cells. Wielowiejski, 1 

 in describing the fine tracheae of the phosphorescent organs, thinks 

 that the tracheal endings (tracheal capillaries) rarely end blindly, 

 but anastomose with one another, forming an irregular network. 



'cap 



FIG. 398. Tracheal net-work of the male glands of Lampyrin nplendiflnJn : 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. 



Fn;. 309. Tracheal capillary end-network (tr. c. .) of silk glands of Ociieria -lixpar: />, 

 peritoneal (peritracheal) membrane. After Wistinghausen. 



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. Wistinghausen have completely disproved the view of Srlnilt/f. that 

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

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



