The Structure of Insect Flii;ht Muscle 



203 



Fig. 1. Longitudinal section of insect flight muscle, showing array of logitudinal lilaments. No I-bands are visible. 

 Magnification 22,000. 



Fig. 2. Longitudinal section of same muscle at higher magnification, showing secondary filaments between the primary 

 filaments; primary and secondary filaments appear to be connected together by a system of bridges. Magnification 

 < 135,000. 



Fig. 3. Cross-section of insect flight muscle showing double array of filaments: six secondary filaments may be seen 

 around each primary filament, and each secondary filament is located midway between two primary filaments. Magnifica- 

 tion X 135,000. 



