44 Annals Entomological Society of America [Vol. XIII, 



116. The First Retractor of the Spermatophore Cup (Figs. 

 35 and 36) originates from the anterior end of the ventral valve 

 at its junction with the ductus, runs obliquely round the cup 

 and is inserted into the lateral side of the dorsal valve at the 

 posterior end where the chitinous plates are given off. 



117. The Second Retractor of the Spermatophore Cup (Figs. 

 35 and 36) is similar to the first retractor in origin and insertion 

 and lies between it and the cup. 



118. The Dilator of the Mouth of the Spermatophore Cup 

 (Figs. 35 and 36), a very short, straight muscle having its origin 

 on the dorsal side of the dorsal valve and its insertion adjacent 

 to that of the retractors. 



119. The Constrictor of the Spermatophore Cup (Figs. 35 and 

 36) forms a muscular tunic covering the outer surface of the 

 dorsal valve of the spermatophore cup. The action of this 

 muscle and of the retractors forces the spermatophore out of the 

 cup. 



(b) Female Genital Muscles. 



120. The Protractor of the Ovipositor (Fig. 33) is a short, 

 stout muscle which originates from the process of the supra- 

 genital plate (P. S. G.) and is inserted into the inner face of the 

 ventral process of the dorsal gonapophysis. Pulls the ovi- 

 positor backwards. 



121. The Lateral Abductor of the Gonapophyses (Fig. 33) also 

 originates from the supragenital process and is inserted into the 

 dorsal process of the ventral gonapophysis. It pulls the two 

 gonapophyses of one side apart from those of the other side, at 

 the same time enlarging the genital orifice which lies between the 

 bases of the ventral gonaphyses. It also elevates the ovipositor. 



THE MECHANICS OF THE OVIPOSITOR. 



The two plates on each side are enabled to work together 

 (1) by a tongue and groove joint which runs along their entire 

 length and (2) by the interlocking of the dorsal processes. 

 (Fig. 3). 



The ovipositor is a lever of the first order, the inner processes 

 being the force arms, so that an upward or downward pull on 

 these processes, respectively depresses or elevates the external 

 plates. Similarly an inward pull (the transverse beam being 

 the fulcrum in this case) separates the right and left plates 

 • externally. 



