1880. | The Proboscis of the House-fly. 155 
In the central axis of the mid segment, and closely articulated 
to the front processes of the fulcrum, is a plate (Fig. 3, x) longi- 
tudinally curved upwards so as to embrace the operculum, and 
with it to form a canal. Its central axis and its lateral parts are 
thickened. Lowne calls it the cannula. It may be convenient to 
refer to its lateral arcuate thickenings as the trabeculoid arches. 
Lying in the channel formed by the operculum and cannula, 
and firmly articulated be- 
hind with the front end of 
the fulcrum, is the lingua, 
or hypopharynx (Fig. 3, 2). 
This is rather short in the 
house-fly, but is long in 
Stomoxys, serving as a 
piercing organ. Fic. 3.—Arrangement of hard parts of mid 
Th ; segment (mentum not here shown). 0o, opercue 
e opercular piece and lum, sending back the great tendons, ¢; x, the 
the hypopharynx habitually pais Pee or canna = ed partal 
lie on the axis piece, whose it). In front of the trabeculoid arches are seen 
edges overlap it, but they the beginnings of the circum-orai rods. 
may be started up so.as to project clear above the sheathing mem- 
brane of the mid segment without any rupture of the membrane. 
The distal segment, or tip, called “knob” in Burmeister’s 
Entomology (Fig. 1, A and Æ, Z), is a singular scraping and 
suctorial apparatus, with the oral opening in its upper part set 
amidst the large protrusible lips. When spread out its surface is 
covered by a system of about eighteen pairs of curved trans- 
verse ridges. These have a general resemblance to trachee. 
Suffolk! calls them pseudo-trachez, that is, false trachee. They 
are split tubes, having a rent along their anterior surface, and are 
Supported by a framework of chitinous semi-tubes, which are — 
forked at alternate ends (Fig. 1, D, shows the relation of two 
of these false tracheæ with the ‘intervening membranous crenula- 
tions). The line of opening of these tubes is zigzag, caused by — 
the sheath-membrane flapping over the forked terminations of 
their supporting semi-tubes? This line of opening can be shut — 
So as to produce a closed channel, or opened and made rough 
like the face of a file. ake 
= On the Proboscis of the Blow-fly,’” by W. T. Suffolk, in Monthly Microscopi- 
cal Journal, June, 1869. - ie ee 
igs described and figured by G. Hurst in Quarterly Journal cf Microscopical = 
€, 1856, p. 238. Fig. 1, D. i Ee ee ARS y 
