INDEX. 769 
Post-scutellar region, 183, 185 
Post-scutellum, 169, 170, 183 
Poulton on development of male 
organ, 732 
on number of abdominal seg- 
ments, 729 
Power on foot of Fly, 195 
Prefacial region, 115 
Prelabrum, 115, 148, 150 
Preoral ganglia, 63 
Preoral somites, 15 
Preparation of embryo, 347 
Preretinal membrane, 512, 513 
Prescutum, 166 
Prestomal sclerite of larva, 43 
Prestomum, 144 
Presutural ridge, 176 
Primitive band, 13, 243, 245 
contraction of, 246 
relation of, to membranes, 241 
to nervous system, 479 
structure of, 246 
Primitive fibrillee of muscle, 285 
Primitive groove, 246 
Primitive trace, 253 
Primordial sexual cells, 693 
Proboscis, 127, 390 
air channels of, 398 
air-sacs of, 396 
azygos air-sac of, 398 
bibliography of, 127 
comparative anatomy of, 149 
development of, 130, 148 
in nymph, 321 
exoskeleton of, 127 
exsertion of, 377 
immature condition of, 148 
mechanism of, 390, 395 
morphology of, 130, 147 
movements of, 139 
muscles of, 391 
nerve end-organs of, 402 
oral lobes of, 393 
soft parts of, 390 
suckers of, 4o1 
Procephalic lobes, 14, 63, 114 
changes of, in embryo, 259 
Procerebral lobe, 455 
development of, 494 
Proctodeum, 248 
cuticle of, 282 
of imago, 412 
Prodorsal arch, 177 
Progenital somite, 728 
Progenital sternum, 728, 739 
Progenital tergum, 737 
Pro-imago, 340 
Pronymph, 296 
contractions of, 303 
infra-cesophageal ganglia of, 313 
Prophragma, 177 
Propterygium, 163 
Prosternal area, 178 
Prosternum, 173, 189 
sensory organs of, 179, 217, 633 
Protandry, 723, 724 
Prothoracic apodeme, 177 
Prothoracic horns. See Stigmatic 
cornua 
Prothoracic region, 179 
Prothorax, dorsal arch of, 166 
Protocerebron, 442 
Protoplasm, 264 
Proventricular ganglion of imago, 409 
of larva, 57 
Proventricular ring, 57, 314 
Proventriculus, 52, 408 
cell fibrillation in, 280 
development of, in embryo, 422 
function of, 409 
general morphology of, 52 
of imago, 408 
of larva, 56 
Proximal intestine, 410 
of larva, 58 
origin in nymph, 429 
Pseudo-cone, 516, 528 
origin of, 551 
Pseudo-conic eye, 519 
Pseudo-hzmal vessels, 358 
Pseudo-labium, 141 
Pseudo-pupils, 577, 579 
Pseudo-trachee, 146 
structure of, 393 
Pseudo-yelk, 298 
formation of, 4 
use of, 4 
Pterophorus, eye of, 524 
Ptychoblast, 241, 243, 
dorsal, 255 
Pulex, mouth organs of, 151 
movements of trachez in, 383 
pygidium of, 629 
| Pulvillus, 195 
Pupa, 20 
coarctata, 20 
loss of weight in, 309 
obtecta, 20 
