60 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



immediately underneath the integument, below the pleural su- 

 ture ; they run between an inferior cunea in front and the following 

 inferior cunea (fig. 3). 



(st-i). Small oblique muscles between' sternum and the infe- 

 rior cunea (fig. 2). 



(s-fw 7 -sc). Longitudinal muscles from the superior cunea above 

 the superior cuneal notch, across the scutellum to the scutum. 



(s-fw-scl). Oblique muscles from the superior cunea to the 

 scutellum (fig. 3). 



(an-tetpl). An oblique, single, small muscle from the anterior 

 cuneal notch to the superior part of the tetrapleurite (fig. 4). 



(an-sri). A vertical pair of muscles from the anterior cuneal 

 notch to the superior cuneal notch (fig. 4). 



(an-pri). A single, horizontal muscle between a .posterior 

 cuneal notch and the anterior cuneal notch of the following inter- 

 segmental skin (fig. 3). 



(vn-dpl). One or two large, oblique muscles from the ventral 

 cuneal notch to the anterior curve of the pleural suture below the 

 deuteropleurite (fig. 4). 



(dpl-fw-s). An oblique, short, but rather broad band from the 

 anterior curve of the pleural suture below the deuteropleurite 

 to the superior cunea near the spiracle (fig. 4). 



(dpl-prst). A vertical muscle from the anterior curve of the 

 pleural suture below the deuteropleurite to the presternum. (This 

 I have found only in Trogosita, fig. 6.) 



(spa-pn) . A pair of perpendicular muscles between the poste- 

 rior cuneal notch and the spiracular area just below the spiracle. 



(pl-hypl). One or some few small vertical muscles from the 

 middle of the pleural suture to the hypopleural line (fig. 4, fig. 

 6, 2. Not found in Alaus.) 



(tetpl-hypl) . A vertical muscle from the tetrapleurite to the 

 hypopleural line (fig. 4). 



(pscl-hypl). A long, perpendicular muscle from postscutellum 

 to the hypopleural line, the definition of the postscutellar line 

 (fig. 2). Seep. 58. 



In the preceding I have endeavored to demonstrate that the 

 abdomen of the larvae under consideration is made up, in an 

 identical manner, of the intersegmental skin, the lateral zone, and 

 the regions above and below the lateral zone, and further that the 

 arrangement of the muscles between these parts is uniform. This 

 remarkable uniformity of structure has been preserved through- 

 out the genetic evolution because it enables and conditions the 

 elementary movements of the abdomen. These elementary 

 movements are but two. First, the telescoping of the segments, 



1 fw indicates "forwards to;" bw indicates "backwards to." 



