CHAPTER X. 



THE TRACHEAL SYSTEM OF THE IMAGO. 



1. GENERAL MORPHOLOGY AND DEVELOPMENT OF THE 

 TRACHEAL SYSTEM IN INSECTS. 



a. General Arrangement of the Tracheal System. 



ALL perfect insects, if the doubtful case of some Collembola be 

 excepted, breathe by means of a tracheal system, and respire 

 air, which enters the tracheae by external openings termed 

 spiracles. In some aquatic larvae, however, spiracles are 

 absent, and the tracheal system is said to be closed; such larvae 

 usually possess tracheal gills. 



The spiracles do not open immediately into the tracheae 



Bibliography : 



148. MALPIUHIUS, MARCELLUS, ' Dissertatio Epistolica de Bombyce 

 Societati regime.' Londini, 1669. 410. 



149. MEYER, H., ' Ueber die Entwickelung des Fett-korpers, der Tracheen 

 und der Keimbereitenden Geschlechtstheile bei den Lepidopteren.' 

 Zeitsch. f. w. Zool, Bd. i., 1849. 



150. LANDOIS, H., ' Der Tracheenverschluss bei den Insecten.' Zeitsch. 

 f. w. Zool., Bd. xvii., 1867. 



151. GEGENBAUR, C., ' Grundziige der Vergleichenden Anatomic,' ii. 

 Auf. Svo. Leipzig, 1870. 



152. SEMPER, C., ' Die Stammesverwandtschaft der Wirbelthiere und 

 Wirbellosen.' Arb. aus d. Zool-zoot., Inst. zu Wiirzburg, Bd. ii., 1875. 



153. PALMEN, I.A., 'Zur Morphologie desTracheensystems.' Helsingfors, 



1877, Svo. 



154. KRANCHER, O. (aus Schneeberg), ' Der Bau der Stigmen bei den 



Insecten.' Zeitsch. f. w. Zool., Bd. xxxv., 1881. 



155. HURST, C. H., ' The Pupa Stage of Culex : an inaugural dissertation 

 for the Degree of Ph.D. in the University of Leipzig.' Svo., Leipzig. 

 1890. 



24 



