772 
Simulia, 154 
development of, 254, 256 
mouth of, 154 
Sinus, pericardial, of larva, 87. See 
Blood sinus, Pericardial sinus 
Sirex, ovipositor of, 733 
Sitaris, metamorphosis of, 18 
Skeletal muscles, development of, 287 
Skeletal structures of proboscis, 127 
Skeleton, appendicular, 1o1 
somatic, 101 
Smaller house-fly. See Musca corvina 
Somatic nervous system, 8, 62, 433 
of larva, 67 
Somatic skeleton, ror 
Somatopleure, 16 
development of, 251 
segmentation of, 252 
Somites, 8 
number of, in embryo, 15 
primary, 157 
Sound-producing organ, 217, 595 
Sound-waves, Airy on, 619 
Specific characters of Blow-fly, 31 
Sperm and Germ development com- 
pared, 719 
Spermatheca, 677 
Spermatogenesis, 692, 720 
Spermatospores, 693 
Spermatozoa, 695, 697 
movements of, 698 
Sphinx euphorbiz, eye of, 527 
ligustri, aorta of, 638 
Spiracles, 12, 319, 358 
abdominal, 359, 363, 373 
anterior of larva, 50 
anterior thoracic, 167, 361 
in Coleoptera, 181 
order of succession of, 372 
inter-segmental, 181, 319, 359 
mechanism of, 361 
median thoracic, 188 
nomenclature of, 180, 358 
posterior, of larva, 49 
development of, 369 
posterior thoracic, 171, 188, 373 
segmental, 359 
thoracic, 359 
tympanic, 358, 363, 624 
upper prothoracic disc. See Spir- 
acular disc 
vestibule of, 50, 352, 361 
Spiracular disc, 84, 316, 319 
Sac, 352, 353 
INDEX. 
Spiracular trunks, 225 
Spiral thread of trachea, 355 
Splanchnic nervous system, 65, 92 
Splanchnoblast, 22 
Spongioplasm, 264 
Squama, 165 
Squamula, 165 
Staining, methods of, 95 
Staphylinidee, larvee of, 18 
Stemma, stemmata. See Ocellus 
Stenobothrus, segmental organ of, 
277 
Sterno-dorsal muscles. See Muscles 
Sterno-pleural suture, 168 
Stigmatic discs, See Spiracular disc. 
Stigmatic cornua, 319 
in Corethra, 370 
Stigmatic plate of larva, 369 
Sting of Hymenoptera, 729, 731, 734 
Stomal plate, 143 
Stomodeum, 13, 422 
cuticle of, 282 
development in nymph, 315 
of nymph, 346 
Stomogastric nerve, 57, 65 
development of, in pupa, 494 
Straus Durckheim on homologies of 
muscle, 219 
on leg muscles, 221 
on mechanism of dorsal vessel, 
650 
on wing muscles, 220 
Stricker on origin of nuclei, 717 
Stroma of nerve centres, 66 
Stuhlmann on egg, 713 
Sub-corneal image, 555, 558 
Sub-corona, 471 
Sub-dioptric space, 545 
Sub-epaulet, 201 
Sub-hypodermal cells of larva, 37 
Suckers of proboscis, 394 
Suckow on origin of gonads, 685 
Suction, act of, 399 
Supra-cesophageal nerve centres, 448, 
475 
Supra-tympanic fissure, 176 
organ, 601, 625 
Sutures, 101 
median, 102 
morphology of, 103 
sterno-pleural, 168 
transverse ventral, 169 
Swammerdam on alimentary canal 
of Bee larva, 422 
