ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
283 
from the brain. In front of the superior oesophageal ganglion lies the 
frontal ganglion, from which the oesophago-gastric nerve runs backwards 
beneath the brain close to the oesophagus. Behind the brain it becomes 
connected with the paired system. From the head it extends to the 
thorax, and forms a stomach ganglion. The paired system consists of 
two pairs of ganglia, close behind the brain, connected by commissures 
with one another and with the unpaired system. In short, the system is 
like that of Orthoptera. 
New Scale-Insects.'* * * § ' — Mr. W. G. Johnson describes five new species 
of scale-insects : — Aspidiotus forbesi on cherry, apple, pear, plum, &c. ; 
A. comstocki on sugar maple ; A. sesculi on buckeye ; A. ulmi on white 
elm ; and Chionaspis americana on the same. 
8. Arachnida. 
Oogenesis in Pholcus.f — Prof. Ch. Van Bambeke describes the 
changes in the ovarian ovum of Pholcus phalangioides Fuessl. during 
the period of growth. Four stages may be distinguished, especially as 
regards the formation of the nutritive vitellus. 
(1) First there is the appearance and development of a structure 
which probably represents the vitelline body of Balbiani. 
(2) Then follows the disintegration of this vitelline body. 
(3) The third stage is marked by the fact that the elements derived 
from the disintegration of the vitelline body are transformed into fatty 
drops and granules. 
(4) In the fourth stage the germinal vesicle loses its definite wall, 
and comes into more intimate relations with the cytoplasm. The latter, 
becoming more active, secretes or elaborates the materials which give 
rise to the vacuolisation of the vitellus. The adipose granules pro- 
bably furnish the material which renders the cytoplasm more capable 
of forming the vitelline spheres or true nutritive vitellus. 
Mites and Ants.J — Herr E. Wasmann discusses the myrmecophilous 
mites which infest ants. They occur in the Hypopus- form, and it seems 
difficult to refer them to their proper genus, Tyroglyphus or some other. 
A single ant may bear hundreds or even thousands of mites, all lying 
in the same way, with their head pointing to the apex of the part on 
which they are fixed. Wasmann also speaks of the “ syntrophy ” of 
Lselaps oophilus Moniez, which occurs freely on the surface of the 
eggs of ants ( Formica sanguinea and F. rufobarbis ), but without doing 
them any damage, apparently depending on the salivary secretion of 
the ants, which are always licking their eggs. 
e. Crustacea. 
.Pigments of Lobster. — Miss M. I. Newbigin § has investigated the 
pigments of Homarus , Nephrops, and Astacus. She succeeded in obtain- 
ing a blue pigment in solution from the exoskeleton of Homarus and 
Astacus , and believes that this pigment is of the nature of an unstable 
* Bull. Illinois Lab. Nat. Hist., iv. (1896) pp. 380-95 (6 pis.), 
t Bull. R. Acad. Belg., xxxiii. (1897) pp. 307-21, 
% Zool. Anzeig., xx. (1897) pp. 170-3. 
§ Journ. Physiol., xxi. (1897) pp. 237-56. 
