64 
Psyche 
[April 
The spiracle st between the pro- and mesothorax (Figs. 1 
and 5) is mesothoracic in origin, and should therefore be spoken 
of as the meso-thoracic spiracle, despite the fact that it is very 
closely associated with the prothoracic region. The second 
spiracle is metathoracic, and the third one is the first abdominal 
spiracle. The mesothoracic spiracle is usually located in the 
membranous region continuous with that containing the spina- 
sternite ss (Figs. 1 and 5), particularly in larval forms, and this 
may indicate that the supposed prothoracic spinasternite is 
mesothoracic rather than prothoracic. In any case, this sternite 
may be referred to as the spinasternite, although if it belongs to 
the mesothorax (as its association with the spiracle in other 
insects seems to indicate) the term poststernellum, applied to it 
by some investigators, is hardly applicable, since it would then 
be the anteriormost mesothoracic sternite, instead of the post- 
eriormost prothoracic sternite (as the name “poststernellum” 
would indicate). The relation of the spiracles to the thoracic 
sclerites, the mechanism of the thoracic spiracles, and similar 
topics will be discussed in a paper dealing with the respiratory 
system of the roach, and n f eed not be further discussed here. 
As is shown in Fig. 12, the pronotal plate or “pronotum” 
is divided into a disk or central portion labelled disc and a mar- 
ginal region or limb labelled limb, whose lateral areas are called 
paranota. The ventral indexed margins of the pronotum are 
closely applied to the dorsal surface of the pronotum (above) 
and the edges of these margins apparently exert a tension, re- 
sulting in the formation of faint lines such as those indicated by 
the dotted lines bordering the disk of the pronotum shown in 
Fig. 12. In the -discal region, labelled disc, are several muscle- 
scars, or myocicatrices, etc., which need not be further discussed 
at this time, since they will be described in a paper dealing with 
the muscular system of the roach. The pronotal plate probably 
corresponds to the eunotum (or wing bearing plate) of the other 
thoracic segments, in which a prescutum, scutum and scutellum 
are secondarily demarked in the eunotum of the meso — and 
metathorax, but these areas are not demarked in the pronotum. 
The poorly chitinized and pigmented area labelled psll in Fig. 
16, probably represents the postscutellum of the other thoracic 
