1974] 
Parsons — Pterothorax of Cryphocricos 
43 
a stereoscopic microscope. The attachment of Muscle 70 was studied 
by cutting the tergum sagittally, with a razor blade; the cut Was 
made half way between the ventral phragmal process and the base of 
the mesothoracic wing. A few Pelocoris femoratus Palisot-Beauvois, 
preserved in Bouin’s fluid, were also examined for comparison. 
Most of the Cryphocricos were micropterous, lacking hindwings 
and indirect flight muscles and possessing forewings which reached 
only as far as the third abdominal segment. Only two of the rare 
macropterous forms, with forewings and hindwings extending nearly 
to the tip of the abdomen, were available for the investigation. Al- 
though they were not extensively dissected, their indirect flight mus- 
cles appeared to be either degenerate or absent. 
Newly-moulted Cryphocricos could be distinguished from older 
individuals by the thinness of their exoskeletons and by the distinct- 
ness and relative thickness of the underlying epithelial layer. In 
older specimens the epithelium was thinner, less distinct, and easily 
torn, and the thickened exoskeleton had a layered appearance, prob- 
ably owing to the deposition of successive internal layers of endo- 
cuticle after ecdysis, as Neville (1970) has observed in several in- 
sects. These layers could be peeled away from each other in an older 
specimen of Cryphocricos which had been immersed for 24 hours in 
a concentrated solution of potassium hydroxide. 
Observations 
Typical Naucoridae 
(figs. 1, 5) 
In most macropterous naucorids, such as Pelocoris, the posterior 
margin of the mesothoracic notum (fig. 1 ; N II) is evaginated, form- 
ing a double-walled scutellar lobe (SL). The opening into the lobe 
(OSL) extends anterolaterally to the base of the forewing (WB). 
Immediately ventral to this opening lies the well developed meso- 
thoracic postnotum (PN), which bears the second phragma (PH). 
The postnotum separates the metathoracic notum (N III) from the 
scutellar lobe and is mostly concealed by the latter externally. Only 
its most lateral part, which joins the mesothoracic epimeron (EM), 
forming a postalar bridge, is externally visible. The postalar bridge 
bears a large sensory membrane (SO), part of the mesothoracic 
scolopophorous organ (Larsen, 1957). 
The concealed medial portion of the postnotum forms a two- 
walled, vertical invagination, the second phragma (PH). The 
