5H 
Psyche 
[September-December 
thoracic epimeron and sternum (Fig. i, EM I, ST I), the meso- 
thoracic epimeron, episternum, and sternum (EM II, ES II, ST II), 
the metathoracic episternum (ES III), and all seven ventral ab- 
dominal paratergites (PT 2-PT 8). They also cover all of the third 
and seventh abdominal sternites and all but the anteromedial por- 
tions of the fourth through sixth sternites (ST 4-ST 6). 
The close spacing of the hairs makes it difficult to see their bases 
and to measure their length. Their visible portions are at least 6 /xm 
long and from 0.25 to 0.45 /xm in diameter on the thorax and para- 
tergites (Fig. 4). They are considerably shorter and wider on the 
abdominal sternites; on a sagittal cut through the fifth sternite, 
where the entire length of a few hairs was visible, they were only 
2.7 /xm long but 0.65 /xm in diameter. 
Comparison of the thoracic and paratergal hairs with the plastral 
hairs of Aphelocheirus (Fig. 5) shows similarities which strongly 
suggest that those of Cryphocricos (Fig. 4) are also plastral devices. 
The most striking similarities are ( 1 ) the presence of small nodules 
on the basal portions of the hairs, (2) the densely-packed arrange- 
ment of these hairs, and (3) the posterior bending of their apical 
portions, which lack nodules. Using the light microscope and trans- 
mission electron microscope, Thorpe and Crisp (1947a) observed the 
bending of the hairs in Aphelocheirus but did not see the nodules. 
The bending appears to be more pronounced in both specimens of 
Aphelocheirus than in the three specimens of Cryphocricos. In both 
genera the hairs tend to adhere to each other in clumps, making the 
direction of the bending difficult to detect in surface view (Fig. 3) ; 
the clumping is probably an artifact. 
Fig. 3. Cryphocricos barozzii; surface view of apical parts of plastral 
hairs on metathoracic episternum. More basal parts of hairs, with nodules, 
visible at lower left. Clumping of tips is probably an artifact. Left = pos- 
terior, right — anterior. Scale line = 2 /xm. 
Fig. 4. C. barozzii; clump of plastral hairs on fifth ventral abdominal 
paratergite. Leaf-like setae, which concealed these hairs, were scraped 
off during preparation of specimen. Bases of hairs were concealed by tips 
of surrounding hairs. Note posterior (to right) bending of apices and pres- 
ence of nodules on proximal parts of hairs. Scale line = 1 /xm. 
Fig. 5. A phelocheirus aestivalis ; cut edge of metathoracic episternum, 
showing full length of plastral hairs. Note posterior (to right) bending 
of apices and presence of basal nodules. Scale line = 1 /xm. 
