ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
55 
Respiratory Movements of Coleoptera.*— Sig. L. Camerano does 
not agree with Plateau’s conclusion, that the special expiratory muscles 
are wholly abdominal, for in Melolontha vulgaris , Hydrophilus piceus , 
Cardbus italicus , and Dytiscus marginalis, he finds that the metathorax has 
proper respiratory movements, produced by special expiratory muscles, 
which contract at the same time as those of the abdomen. 
Orthoptera of Galapagos.f — Mr. S. H. Scudder remarks on the 
extreme poverty of the Orthopterous fauna under the equator ; only 
fifteen species appear to be endemic in the Galapagos, and all these are 
distinctly allied to fauna from South and Central America. Five are 
apterous or subapterous, and a sixth has an apterous female. Mr. Scudder 
thinks that the explanation of these facts is to be found in supposing 
that the islands are of a very recent origin, and have obtained their 
present Orthopterous fauna by the chance advent of pregnant females 
as waifs from the nearest shore ; a wingless form would stand the best 
chance, as it would have less inclination to leave the drift-wood or 
whatever kept it above the water. Some have, of course, reached the 
islands by flight. 
8. Araclmida. 
Endosternite of Arachnida.J — Herr W. Schimkewitsch finds that 
this structure is composed of two parts : — (1) of a transversal muscle 
corresponding to the adductor muscle in Crustacea, and (2) of a pair or 
perhaps several pairs of mesodermic tendons connected with the transverse 
muscle- strands. 
Stigmata of Arachnida.§— Mr. H. M. Bernard comes to the con- 
clusion that the tracheal invaginations of the ancestor of the Arachnids 
were strictly segmental, and that they were of some simple tubular 
form, from which the laminate form could be easily developed. Every 
segment appears also to have borne a pair of legs, so that the ancestral 
form had a considerable resemblance to those of the Myriopoda and 
Hexapoda, though differing from them in having the rows of stigmata 
ventral instead of lateral, together with specialized oral appendages. 
Later modifications of the primitive Arachnid were the differentia- 
tion! of the body into cephalothorax and abdomen, and the loss of the 
abdominal limbs, vestiges of which persist as genital opercula, pectines 
and spinning mamillae. The absence of traces of stigmata from the 
second and third segments may be due to the fact that, in the formation 
of the mouth-parts, the first three segments early fused together. 
Mr. Bernard is of opinion that his investigations on the com- 
parative morphology of the Galeodidae go far to establish the classifica- 
tion which ranks the Arachnids as an independent group of the tracheate 
Arthropoda, “ as distinguished from that which would deduce them from 
the specialized Crustacean Limulus through the specialized Arachnid 
Scorpio” 
Instincts of Common English Spiders. || — Mr. R. I. Pocock has some 
interesting notes and observations on some common English spiders. 
* Atti R. Accad. Sci. Torino, xxviii. (1892-3) pp. 590-5. J 
t Bull. Mus. Comp. Zool., xxv. (1893) pp. 1-25 (3 pis.), 
t Zool. Anzeig., xvi. (1893) pp. 300-8 (3 figs.). 
§ Nature, xlix. (1893) pp. 68 and 9 (l fig.). || Tom. cit., pp. 60-3. 
