Studies on Arthropod Cuticle, IV. An Electron Microscope Survey of the Intima of Arthropod Tracheae

A preliminary description of the appearance of the tracheal intima of a few arthropods was given during exploratory work on the application of electron microscopy to entomological problems (Richards and Anderson, 1942a, b; Anderson and Richards, 1942). The present paper is the result of a survey made to determine the number of tracheal types in arthropods and to locate species which are most favorable for an electron microscope analysis of tracheal wall structure. The data presented herein are given to illustrate the range of variation seen in surface views of the intima of tracheae and tracheoles in a representative series of arthropod species. Some discussion is also given on the nature of the forces that might produce tubes of these diverse types, but the extreme difficulty of obtaining critical data on such minute tubes necessarily makes the discussion largely a speculative rationalization. In a subsequent paper we plan to analyze the cross-sectional composition of the tracheal walls of a few representative species in more detail.