PSYCHE 



VOL. XXVIII JUNE. 1921 No. 3 



MUSCULATURE AND MECHANISM OF MOVEMENT OP 

 THE TARSI IN APHIDS.i 



By Leopoldo B, Uichanco, 



College of Agriculture, University of the Philippines, 



Los Baiios, P. I. 



The present work is an attempt to determine the muscles respon- 

 sible for the movement of the tarsi in aphids. The manner of 

 articulation of the first tarsal segment on the tibia and the mech- 

 anism of movement of the tarsi are discussed in some detail. 



Material and Methods. 

 The form used was Myzus persicce Sulzer, Like many other 

 aphids, this species is a very favorable subject for anatomical study 

 of the appendages on account of the semi-transparent condition 

 of the integument, which renders the interior more or less visible, 

 even in the living specimen. Two series were studied: (1) living 

 material and (2) balsam preparations in toto. For the study of 

 the living insects, both n3'mphs and adults, mounted in aqueous or 

 saline media, were used. In these it was })Ossible to follow the 

 movements of the tarsi under both the 16-millimeter and the -i-milli- 

 meter objectives of an ordinary Bausch and Lomb microscope fitted 

 with a No. 10 ocular. The muscle responsible for the movement 

 and its tendons also showed a fairly sharp definition in the fresh, 

 unstained preparations. Amputated legs were likewise studied, 

 although not used as a basis for the investigation of tarsal move- 

 ments for the reason that the operation might have brought about 

 conditions which would tend to produce abnormal reflexes. A 

 more careful preliminary anatomical study was made of fresii 

 specimens with the aid of Schneider's acid cannine. This reagent 

 was found to stain the nuclei of the hypodermal cells and the 

 muscle bodies deeply, differentiating them fairly well from the 



1 Contributions from the Entomological I^aboratories of the Bussey Institu- 

 tion for Research in Applied Biology, Harvard University. No. 187. 



