DEVELOPMENT OF GYNIPID HYPERPARASITES 467 
lateral expansions over-arching the cavity inside. In effect, 
it partly divides the proctodaeum into two compartments, one 
within the other, and the Malphigian tubules communicate 
ventrally with the inner of the two. The outgrowth or process 
itself is formed of two layers of elongated basophil cells, with 
well-marked nuclei, similar to those of the wall of the hind-gut, 
and in the later stages it almost fills the lumen. If it contained 
muscular fibres it would be easy to suppose that this outgrowth 
functions as a valve, shutting off the orifices of the Malpighian 
tubules from the general proctodeal cavity ; but as the presence 
TExt-FIc. 11. 
rs 
Mig > 
Fas: 
SLY 
Proctodaeum of the young larva, A in sagittal, B in transverse section. 
x 350. c.ep.=columnar epithelium; c¢.m.=circular muscles ; 
J.b.=fat-body ; h.p.=hypoderm; [.m,= longitudinal muscles ; 
l.pr.= lumen of proctodaeum ; mes.ep.=epithelium of mesenteron ; 
8.p.= process projecting into the lumen of the proctodaeum. 
of muscular tissue cannot be demonstrated, its only purpose 
appears to be to increase the surface area of the columnar 
epithelium of the hind-gut (Text-fig. 11). 
The two Malpighian tubules are exceedingly short. Hach 
is composed of eight or nine large cells only, but these 
surround a lumen of considerable diameter. The nervous 
system appears as a broad slightly-constricted band. The 
supra- and sub-oesophageal ganglia, and the three ganglia of 
the thorax, are well marked; but those of the abdominal 
region are indistinctly separated, with the exception of the 
last two, which are fused and form a distinct bulb-like swelling. 
NO, 259 Ki 
