ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
781 
tropical zone of America, have been found living in the skin of Man. 
He points out that not one of them is peculiar to Man, and that, there- 
fore, the old belief in an CEstrus hominis must be abandoned. 
Digestive Tract of Gryllotalpa vulgaris.* * * § — Herr J. Eberli has 
made a detailed examination of the digestive tract of this Insect, devoting 
most of his attention to the stomach ; he finds that the four lamellm which 
extend into the hind-gut are structures which arise from four longitu- 
dinal stripes in the stomach. There is no funnel in Schneider’s sense in 
Gryllotalpa ; the function which he ascribed to it is performed by the 
four lamellae, and while these form a filter they serve as a protecting 
apparatus to the hind-gut. It is clear that the stomach is not to be 
regarded as a comminuting organ of the food ; one of its functions is 
to aid the passage into the saccules of the mid-gut of nutrient particles 
which have been finely divided by the chitinous denticles. 
The hind-gut is much longer than the first two portions, and may 
be divided into four subdivisions; there is an infundibular portion 
which narrows posteriorly, a second which is much wider and receives 
the openings of the Malpighian vessels, there is a third narrower piece 
and a wide rectum. 
Spermatogenesis in Gryllotalpa.! — Dr. 0. vom Rath describes the 
spermatogenesis of Gryllotalpa vulgaris Latr., and pays particular atten- 
tion to the question of “ reduction-divisions.” The important point is 
that in the sperm-mother-cell at the beginning of the second last division 
the number of chromosomes is double the typical number ; in the second 
last division the doubled number is reduced to the normal, ami in the 
last division halved. The result was confirmed by observations on 
Hydrophilus , Astacus , Branchipus , and various Copepods, &c. It supplies 
an additional basis of fact for Weismann’s conclusions. 
Anatomy of Phylloxera.! — Herr J. Krassilstschik has some pre- 
liminary notes on the structure of Phylloxera vastatrix, describing espe- 
cially a complex salivary pump which he has discovered, and also dis- 
cussing the precise mechanism of sucking. The minute dorsal tubercles, 
the retort-shaped organs discovered by Metschnikoff, the musculature, 
the fatty tissue, and the pseudovitellus whose cells are scattered in small 
groups in the fatty tissue, are also noticed ; and the close relationship 
of Phylloxera to Coccidae is maintained. 
Oral Appendages of Thysanura and Collembola.§— Rudolph Ritter 
von Stummer-Traunfels describes these in Japyx, Campodea, and Col- 
lembola, interpreting them as (1) mandible, (2) maxilla (without galea 
or palp), and (3) labium, with palp, and including ligula and paraglossae. 
In Japyx and Campodea there are inner and outer paraglossse, the latter 
with palp ; in the Collembola there are only the inner paraglossse, the 
outer having fused with the palp. After a comparison of the above- 
mentioned forms with those of Machilidse and Lepismidae, the author 
notes the essential uniformity throughout the order, which he divides 
* Vievteljahrschr. Naturf. Gesell. Zurich, xxxvii. (1892) pp. 167-212 (10 figs.). 
f Archiv f. Mikr. Anat., xl. (1892) pp. 102-32 (1 pi.). 
% Zool. Anzeig., xv. (1892) pp. 217-23 (1 fig.). 
§ SB. K. Akad. Wiss. Wien, c. (1891) pp. 216-35 (2 pis.). 
