1974] 
Parsons — Pterothorax of Cryphocricos 
45 
phragma is especially pronounced on either side of the midline, where 
it bears a pair of large ventral processes (fig. 5; VP) upon which 
two of the mesothoracic indirect flight muscles attach (Muscles 30 
and 31 of Larsen, 1945; present but degenerate in most Pelocoris ) . 
According to Snodgrass (1935) the phragma represents the pri- 
mary boundary (antecosta) between the metathorax and mesothorax, 
and the mesothoracic postnotum is thus an intersegmental plate which 
is only secondarily associated with the mesothorax. This interpreta- 
tion, which has been challenged by Matsuda (1970), is supported by 
the fact that the posterior wall of the phragma is continuous with 
the metathoracic episternum (fig. 1 ; ES). 
Muscle 70 (fig. 1 ; M. 70) originates posterior to the phragma 
and postnotum, its fibers attaching only on the metathoracic notum. 
The latter forms a sharp angle with the posterior wall of the 
phragma. The angle is sclerotized medially (fig. 1) but contains a 
narrow membrane laterally (fig. 5; MEM). The membrane lies 
immediately anterior to the origin of Muscle 70. 
Macropterous Cryphocricos 
(fig- 2 ) 
Most of the typical structural relationships described above are 
also present in macropterous Cryphocricos. In the latter, however, 
the postnotum forms a definite, double-walled second phragma only 
near the midline, at and between the ventral processes (position same 
as in micropterous Cryphocricos , figs. 6, 7). Lateral to the ventral 
processes the postnotum does not seem to be invaginated, and appears 
merely as a transverse thickening (fig. 2, PN) just posteroventral to 
the opening into the scutellar lobe (OSL). Neither of the two 
available macropterous specimens were newly-moulted. It is thus 
possible that a low, double-walled phragmal invagination is present 
in this region immediately after ecdysis. As new layers of endocuticle 
are subsequently laid down, the structure of the phragma could 
become obscured, giving it the appearance of an uninvaginated thick- 
ening in older specimens. 
Laterally the anterior portion of the postnotal thickening forms a 
well-defined postalar bridge with the mesothoracic epimeron (EM). 
The bridge contains a large sensory membrane (SO) similar to that 
of typical naucorids. The posterior portion of the postnotal thicken- 
ing is continuous laterally with the metathoracic episternum (ES) 
and medially with the metanotum (N III). Its boundary with the 
