ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 561 
The flies follow the flights of the Locust, and when they settle on the 
ground to copulate and lay their eggs, they surround them, and bore 
their way to their eggs. The Dipterous genus Iclia is capable of boring 
its way into firm ground, but it is powerless in light and sandy soils. 
This explains why Acridium peregrinum chooses soils of the latter 
kind. 
y . Protracheata. 
Peripatus.* — Mr. B. I. Pocock, in an account of the species of Peri- 
patus of the West Indies, proposes to give generic names to the three 
groups hitherto included under tho common name Peripatus. He con- 
siders that these groups are of considerably greater value than tho 
genera of other orders of animals. 
Peripatus , with the type P. juliformis of Guilding, has the legs fur- 
nished with four spinous pads, and the generative aperture of the adult 
is always situated between the legs of the penultimate pair ; the species 
are found in the Neotropical region and possibly in Sumatra. 
In all other species the legs have only three spinous pads, and the 
generative aperture is behind the penultimate pair of legs. When tho 
latter is between the legs of the last pair and well in advance of the 
anus, the species are placed under Peripatoides ; they are found in 
Australia and New Zealand. In the South African forms, which are 
called Peripatopsis, the genital aperture is behind the last pair of fully 
developed legs, and close to the anus at the hinder end of the body. 
8. Arachnida. 
Vestigial Stigmata in Arachnida.f — Mr. H. M. Bernard points out 
that, if a collection of Thelyphonidae be carefully looked through, it is 
impossible to avoid the conclusion that these Arachnids once possessed 
limbs w'ith stigmata along at least seven abdominal segments, as definite 
scar-like markings, or even sharply circumscribed areas may be seen. 
It seems, from a comparison with Scorpio , reasonable to suppose that 
Thelyphonus originally possessed at least seven pairs of lung-books, five 
of which have now vanished. 
The author is of opinion that the tails of these two genera are not 
primitive structures, but a later specialization ; if, further, it is possible 
to homologize the anal glands of Thelyphonus with the poison-glands of 
Scorpio , and both of these with the original invaginations of the scar 
found on each side of the anal papillae in the Chernetidae, it will follow 
that all these tail-segments once possessed limbs with tracheal invagina- 
tions or their homologues. 
Development of Pulmonary Sacs in Arachnids.:}:— Dr. A. Jawo- 
rowski finds from a study of the development of Trochosa singoriensis 
support for the conclusion first indicated by Schimkewitz that the so- 
called lungs of spiders are in the embryonic state manifoldly branched 
tracheae. He traces the development, showing how the porch or Vorraum 
of the embryonic trachea becomes the so-called lung. The development 
* Journ. Linn. Soc. London, xxiv. (1894) pp. 518-26 and 542. 
f Ann. and Mag. Nat. Hist., xiv. (1894) pp. 149-53 (3 figs.), 
j Zeitschr. f. wiss. Zool., lviii. (1894) pp. 54-78 (1 pi.). 
