382 M. F. Meinert on Mochlonyx (Tipula) 
The head is rounded; the parts of the mouth with the 
second metamere of the head are protruded, oval; the pro- 
boscis is protruded and comparatively large. The labrum is 
elongated, narrowed, slightly arched forwards, with a pair 
of sete inserted on the lower surface a little behind the apex ; 
the dorsal plate of the first metamere (scutwm dorsale metamert 
primt) is but very short, and the larger part of the labrum is 
therefore the posterior, and it is supported at the sides by the 
long thin lateral pieces (epipharynx), which may easily be 
traced back to the pharynx from which they start*. The 
hypopharynx is long, compressed, strongly pointed; it forms 
a deep boat-shaped channel, the anterior extremity of which 
runs out into two short horns, and the sides of which, on their 
outer margins, are furnished with a close fringe of long very 
fine sete. Of the salivary duct I have seen no trace either in 
males or females. The proboscis, as already stated, is exten- 
ded, and the basal part (scutwm ventrale metamert prim? or 
mentum autt.) is large and strongly beset with hairs. The 
ligula is long and conical. The dadella are distinctly two- 
jointed, broad, rounded off in front, with their inner angles 
produced into a short point ; no inner supporting apparatus is 
to be seen. The sculpella (maxille autt.) are tolerably long, 
very acute, thin, nearly membranous, and reach in length 
about to the middle of the labrum or halfway up the third 
joint of the palpus. The pleural processes or cultelli (man- 
dibule autt.) as usual occur only in the females; they are a 
good deal shorter than the sculpella, and of a broader and 
more obtuse form, but likewise thinand membranous Tf. ‘The 
* In presence of the objection lately urged by Kreepelin (Zool. Anz. 
1882, p. 576) against the opinion put forward by Menzbier and defended 
by Dimmock and myself, that the labrum may be regarded as a fusion of 
two different pieces or parts, I willingly admit that the labrum presents 
itself as “eine einfache Ausstiilpung des Kopfes;” but nevertheless I- 
think that the epipharynx cannot be called either an “ Ausstiilpung” or 
a “ Hoblraum,” but only a chitinous prolongation of the upper margin of 
the pharynx ; and it seems to me not improbable that similar chitin ous 
processes may become amalgamated with or lodge themselves in the dor 
sal part of a metamere. For me therefore there can be no question of a 
fusion of two “ Ausstiilpungen ” or of two‘ ‘ Hohlraume.” 
+ In a morphological point of view these pleural processes are of great 
interest, for in Mochlonyxv (and likewise in Corethra) they distinctly ap- 
pear as simple processes without any trace of articulations, so that it is 
very difficult or impossible to assimilate them with the mandibles such as 
we know them in insects with biting mouth-organs (and Hymenoptera). 
But neither can it be denied that they correspond exactly with the organs 
which are known under the name of mandibles in the females of Culex, 
Ceratopogon, Simulinun, and Tabanus, and which I have described in most 
of the genera or families here mentioned under the name of pleural pro- 
cesses or culéelli (cf. Trophi, Dipterorum: Fluernes Munddele). 
