626 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.51. 



which ends in a depressed, slightly chitinized rod, connecting two con- 

 spicuous muscle marks ; the rod is approximately twice as long on the 

 thoracic segments as on the abdominal segments; from the terminus 

 of this rod the hmiting line of the outlying tergal portion continues as 

 a rather indistinct wrinkle to the mark below the gland of the next 

 segment, and hence downward to the tergopleural suture. 



Tliis whole outlying tergal portion corresponds to what I before 

 have called the spiracular area {spa, fig. 1). In most coleopterous 

 larvae, however, including the majority of the Coccinelhd larvae, the 

 spiracles have moved away from this area on the thoracic segments, 

 and the term "spiracular area" would consequently be misleading 

 apphed to these segTaents; while the term wDl be retained for the 

 spiracle bearing abdominal areas, the homologous thoracic areas 

 should be named "the alar areas, "^ because it is from these areas, (al, 

 figs. 1, 2) that the wing pads start on the second and tliird thoracic 

 segments. ^ The central part of tergum is divided by the deep trans- 

 verse suture {tds, figs. 1, 2) ending in the depressed cliitinizations just 

 mentioned hi the foregoing; in front of tliis suture lies the anterior, 

 trapezoidal portion of scutum (sc I, fig. 2), wliich contains a central 

 transverse ridge of setae and a small, triangular prescutum (psc, fig. 

 2) ; behind the transverse fine is the posterior portion of scutum (sc 

 II, fig. 2) with a small, triangular, faintly outhned scutellar area (scl, 

 fig. 2) opposite prescutum. Parascutum {pasc, figs. 1 and 2) is small 

 and not sharply defined. 



The outline of the pleural or lateral zone is concave above and 

 below; dorsally it is defined by the tergopleural or lateral suture (tp, 

 figs. 1,2), ventrally by the sternopleural or sublateral suture (stp, fig. 

 3) ; the latter formerly referred to by the writer^ as the pleural suture. 

 On the thoracic segments this suture runs immediately above the 

 conspicuous double chitinization with which coxa articulates, and on 

 the abdomen^ it connects the anterior and posterior cuneal notches 

 (an and pn, fig. 3) and contains a small muscle mark on the middle of 

 each segment. The pleural or lateral zone is large and bulges out 

 prominently, so that only half of it can be seen from above, the other 

 half from below. The pleural lobe (pll, fig. 3) is central and sur- 

 rounded by the proto-, deutero-, trito- and tetrapleurites (1, 2, 3, 

 4a, 46, figs. 13) ; these are all well developed, especially is the lower 

 part (4&) of the tetrapleurite unusually large and cusliion-hke. 



Both in the thoracic and the abdominal segments the areas below 

 the pleural or lateral zone are the following: Hypopleurum, para- 

 sternum, presternum, sternum or eusternum, and sternellum. The 

 hypopleurum (pcx, fig. 3) is comparatively small in the thoracic seg- 



1 Following suggestion from Mr. F. C. Craighead. 



2 This can be observed in larvae which for any reason abnormally have developed wing pads. 

 » See Boving, The Abdominal Structures, etc., pp. 56-57. 



