Musculature and Mechanism of Movement ofthe Tarsi in Aphids

The present work is an attempt to determine t.he muscles respon- sible for the movement of the tarsi in aphids.The manner of articulation of the firs tarsal segment on the tibia and he mech- anism of movement of the arsi are discussed in some detail. MATERIAL AND ETI-IODS.The form used was Myzus persic Sulzer.Like many other aphids, Chis species is a very favorable subject for anatomical study of the appendages on account of Che semi-transparent conditi.on 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 nymphs and adults, mounted in aqueous or saline media, were used.In these it was possible o follow the movements of the tarsi under both the 16-millimeter and the 4-milli- meter objectives of an ordinary Bausch and Lomb microscope fitted with a 17o. 10 ocular.The muscle responsible for the movement and its tendons also showed a fairly sharp definition in he fresh, unstained preparations.Amputated legs were likewise studied, although not used as a basis for the investigation of tarsal move- ments for Che reason hat he operation might have brought about conditions which would fend to produce abnormal reflexes.A more careful preliminary anatomical study was made of fresi specimens with he aid of Schneider's acid carmine.This reagent was found o stain he nuclei of the hypodermal cells and he muscle bodies deeply, differentiating them fairly well from the Contributions from the Entomological Laboratories of the Bussey Institu- tion