172 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
of tlie first maturation division a coiled thread with chromatic granules 
scattered along its entire length is to be seen. This thread breaks up 
into twelve segments, which become associated in pairs in such a way as 
ultimately to form rings. Each ring becomes a “ Yierergruppe ” by 
the concentration of the chromatic substance into four chromosomes. 
The two maturation divisions which follow result in giving each 
spermatid six chromosomes. 
According to the author’s observations on Caloptenus, both matura- 
ration divisions are reduction divisions in Weismann’s sense, but there 
is no longitudinal splitting of the chromatin thread just before the last 
two divisions ; hence there are no identical pairs of chromosomes, and 
neither of two maturation divisions can be an equation division. 
Biology of Horse-Bot.* * * § — Prof. H. Osborn finds that the eggs of the 
Horse-Bot do not hatch unless they are assisted^by the horse’s tongue ; the 
hatching of the larvae takes place most readily during the third to fifth 
week after deposition. The majority of the larvae die after 35 to 40 days. 
It is possible, though not normal, for eggs to hatch without moisture 
or friction. It is concluded that "scraping off the eggs or their de- 
struction by means of washes will be very effective, even if not used 
oftener than once in two weeks during the period of egg deposition. 
j8. Myriopoda. 
Copulatory Appendages of lulidse.f— Dr. C. G. Attems" finds that 
there is essential resemblance in the copulatory appendages throughout 
the whole genus lulus. As is well known, the copulatory appendages 
occur on the seventh ring ; the first pair are flat lamellae which may bear 
a flagellum (a long hooked bristle with a swollen bulbous base) ; the 
second pair are more complex and more variable. On a groove of the 
second appendage in which the seminal fluid flows there opens the duct 
of a (prostate?) gland hitherto overlooked. The author explains the 
structure in the various types of lulus , and thinks that it is unwarrant- 
able to split up the genus (into 5 genera and 14 subgenera) as Verhoeff 
has proposed. He would recognize only two subgenera — Mastigoiulns 
and jEnantiulus, respectively with and without flagellum. 
5. Arachnida. 
Structure and Development of the Endosternite.J — Herr W. 
Schimkewitsch gives an account of what he and others have observed 
as to the endosternite and its related musculature. He describes the 
ectodermic endoskeleton of Galeodes casjpius. The tissue of the endo- 
sternite consists of fibrils united in bundles and of complexes of cells 
which lie in cavities. It arises from cells which grow inwards from the 
parietal muscular layer, and is a special case of a general tendency to 
replace an ectodermic endoskeleton by a mesoskeleton. 
Development of Acarina.§ — Sig. F. Supino gives some account of 
the development of Acarina, e. g. Psorojotes ovis Gerh, Aleurobius farinee 
* U.S/Dept. Agric. Div. Ent. Bull., xxxii. p. 48; see Amer. Nat., xxviii. (1894) 
p. 964. t Zool. Anzeig., xvii. (1894) pp. 356-9. 
X Zool. Jahrb. (Abth. Anat. Ontog.), viii. (1894) pp. 191-216 (2 pis.). 
§ Atti Soc. Trentina Sci. Nat., ii. (1895) pp. 242-61 (3 pis.). 
