178 General Notes. [February, 
and S. occitanus) cannot cause the death of a human subject, and 
are only dangerous when several poison a man at the same time, 
or attack very young children. To judge by his bibliography, 
the author is unacquainted with the observations on the habits of 
scorpions, published in 1882, by Prof. Lankester.—/ourn. R. Micr. 
Soc., August, 1884. 
OCCURRENCE OF TACHINA FLIES IN THE TRACHE OF INSECTS.— 
N. Cholodkowsky gives in Zool. Anzeiger (June g) an account of 
a young larval Tachina 1 ™™ long found in the ventral stigma of a 
carabus beetle. He afterward found the same kind and another 
species of Carabus infested with fully grown Tachina maggots. 
He also found a Harpalus ruficornis literally packed with these 
larvee. The occurrence of Tachina larve in the bodies of 
grown-up insects is, he adds, no new thing. In 1828 Bohéman 
found in Harpalus ruficornus and aulicus the larve of Uromyta 
curvicauda ; Léon Dufour described Hyalomyia dispar as a parasite 
of Brachyderus lusitanicus ; he also found the larva of Phasia in 
Pentatoma grisea and Cassida viridis and the larva of Ocyptera 
bicolor in Pentatoma grisea. Boye in 1838 took Tachinz from 
three species of Carabus. Within a few years Kinkel d’ Hercu- 
lais found the maggot of Gymnosoma rotundatum in the body of 
Pentatoma. 
Eaton’s MONOGRAPH oF ReEceNr EPHEMERIDE. Part 11.—We 
have already (p. 630) called attention to this elaborate work. 
This part concludes the descriptions of the species as well 
as the nymphs when known. A most important feature of 
this part is the illustration of the nymphs, which have been 
drawn with great detail and engraved by A. T. Hollick, filling 
twenty large plates. Between this magnificent work and the 
elaborate memoir by Vayssiére, as well as the papers of Joly, the 
Ephemerids certainly have no reason to complain; though their 
own lives scarcely span a day, their historians have devoted years 
of research to them. : 
STRUCTURE AND FUNCTION OF THE LEGs oF INsEcTs.—We have 
already called attention to this essay by F. Dahl. The Journal of 
the Royal Microscopical Society for October contains an abstract 
of it, which our entomological readers will find of interest. The 
constancy of the number of six legs is probably to be explained 
as being in relation to the functions of the leg as climbing organs ; 
one leg will almost always be perpendicular to the plane when 
the animal is moving up a vertical surface; and on the other hand 
we know that three is the smallest number with which stable 
equilibrium is possible; an insect must therefore have twice this 
number, and the great numerical superiority of the class may be 
= associated with this mechanical advantage. This theory is not 
weakened, but rather supported, by the fact that the anterior pair 
= of legs is rudimentary in many butterflies, for these are almost 
exclusively flying animals. 
