DIPTERA. 
413 
distinguishes three different tones as emitted by these insects — 
during flight a relatively low tone^ a higher one when the wings 
are held so as to prevent their vibrating, and a higher still when 
the fly is held so that all motion of the external parts is pre- 
vented. The last mentioned is the true voice of the insect; it 
is produced by the stigmata of the thorax, and may be heard 
when every other part of the body is cut away. The first sound 
is caused by the rapid vibration of the wings in the air ; the 
second is caused, or at all events accompanied, by the vibration 
and friction of the abdominal segments, and by a violent move- 
ment of the head against the anterior wall of the thorax. The 
arrangement of the parts by which the stigmata are enabled to 
give origin to the sound produced by them is rather compli- 
cated ; it is described and figured by Landois in Calliphora vo- 
mitoria [1. c. p. 138, pi. 10. figs. 9-12), Eristalis tenax [Lc* 
p. 142, pi. 10. fig. 14, and pi. 11. fig. 13), Scaiophaga stercoraria 
(I, c, p. 145), and Musca domcsiica (/. c, p. 145, pi. 11. figs. 15, 
IG). The author describes the striieturc of the haltercs, which 
arc connected by a lever with the chitinous ring connected with 
the sound- apparatus in tlic hinder pair of thoracic stigraataj 
and, by communicating to this their movements, assist in pro- 
ducing the sound. The vibration of the head in the Diptera 
during the emission of sound is regarded by the author as due 
to the transmission of movement from the thorax. 
ScHiNER (Verb, zool.-bot. Ges. in Wien, xvii. pp. 631-638) 
discusses the remarks made by Gerstacker, in his lleport on the 
entomological literature for 1863 & 1864, upon the new nomen- 
clature of the wing-veins in the Diptera, proposed by Schiner, 
the new classification of Diptera established by the joint efibrts 
of Schiner and Braucr, and the catalogue of European Diptera 
published in 1864. Schiner complains, and in some respects 
justly, of having been misunderstood by Gerstacker; but his 
remarks will hardly admit of being condensed for insertion 
here. 
Brauer also (1. c. pp. 737-744) replies to Gerstacker^s re- 
marks, and especially discusses the nature of the metamor- 
phosis in Cecidomyia destructor and its allies to which Gerst- 
acker appealed as invalidating Brauer’s primary division of 
the Diptera into Cyclorhaplia and Orthorliapha, and indicates 
the difterences which he considers distinguish the Cecidomyice 
with coarctatc pupae from the true Cyclorhctpha. 
Schiner continues his notices of the Diptera collected on the voyage of 
the ^Novara ’ (Verb, zool.-bot. Ges. in Wien, xvii. pp. 303-314). In this 
report ho refers to the species of his families Stratiomyda; to Midasida:. 
Frahenfeld (Verh. zool.-bot. Ges. in Wien, xvii. pp. 432-433 & 449- 
456) notices a series of species of this order collected on board the ‘ Novara.’ 
Some of them are described as new. Cyrtoneiira stahnlans (Meig.) occurred 
on board on the return voyage, in the midst of the Atlantic, in 20° S. lat. 
