NOTES ON THE MESOTHORACIC MUSCULA- 

 TURE OF DIPTERA 



By JOHN SMART, M.A., D.Sc. 

 Department of Zoology, University of Cambridge, England 



(With One Plate) 



1. INTRODUCTION 



The notes presented below grew out of a study, commenced some 

 years ago, of the morphology of Anisopus fenestralis Scopoli (Ani- 

 sopodidae ( = Rhypidae = Phryneidae), Diptera). This study has not 

 been completed for a number of reasons : First, Anisopi{s did not 

 prove as informative phylogenetically as was hoped ; second, Anisopus 

 proved somewhat unsatisfactory as an anatomical subject ; third, the 

 investigations carried out on Anisopus led to some interesting com- 

 parative investigations of the musculature of the mesothorax of Dip- 

 tera in general — the topics of sections 6, 7, and 8 of this paper. 



These notes have a common list of references at the end of the 

 paper, and the final concluding comments on the comparative myology 

 and phylogeny of Diptera draw the materials together. 



2. HISTORICAL NOTES 



The classical works on the musculature of Diptera are the mono- 

 graphic studies of Kunckel (1875-1881) on the drone fly {Eristalis 

 tenax) and Lowne (1890-1895) on the blow fly (Calliphora erythro- 

 cephala). Neither of these works was confined to the musculature, 

 which was treated incidentally to dealing with the entire animal from 

 an anatomical point of view. Furthermore the refinement and artistry 

 of Kunckel's figures and the roughness of Lowne's illustrations both 

 disguise the relative superficiality of their treatment of the muscula- 

 ture, though modern workers should be charitable and keep in mind 

 that these monographs were produced before the Greenhough type 

 of binocular dissecting microscope with its erected image was avail- 

 able to the insect anatomist. 



Modern studies of flight mechanisms, including only incidentally 

 that of Diptera, taking into consideration both the mechanical and 

 physiological problems involved, were largely initiated by von Lenden- 

 feld (1881-1903) and Voss (1905). 



Ritter (191 1), a pupil of von Lendenfeld's, published his paper on 



331 



