564 
MR. NEWPORT ON THE RESPIRATION OF INSECTS. 
into the large vesicles (f ) : (b) small transverse connecting tube, which 
gives off a pair of small tracheae, which, with two others from the large 
tracheae, are developed into a very large, superior, transverse vesicle, which 
lies above the lateral ones in the abdomen : ( d , e) two longitudinally di- 
rected tracheae, which pass on each side of the oesophagus; ( e ) passes down 
to the lower part of the proventriculus, and distributes recurrent branches, 
(d) passes no lower than the anterior part of the proventriculus : ( g ) funnel- 
shaped transverse tracheae, which pass beneath the muscles in the under 
surface of the body : ( i , k) origins of similar vessels, which pass over the 
dorsal surface of the abdomen ( h ) : ( i ) trachea to the duodenum or ventri- 
culus, ( k ) to the small intestines, (Z) to the colon and organs of generation. 
Fig. 3. A portion of the colon and caecum from the perfect insect Phalcena vinula, 
Linn., laid open to show the ramifications of the tracheae in the adipose 
membrane (a), and that they do not ramify in the internal glandular or 
mucous membrane, a part of which is reflected separately ( b ). Magnified 
10 diameters. 
4. A portion of the mucous lining of the colon, studded with glands, and sepa- 
rated from the other structures. Magnified 24 diameters. 
5. One of the antennae of Papilio urticce, Linn, removed from the insect im- 
mediately after changing to the pupa state, and viewed by transmitted 
light, and very highly magnified to show the beautiful distribution of the 
tracheal vessel. 
6. The exterior spiracle with its converging fibres. Magnified 25 diameters. 
7. The internal spiracle, with its valves, muscles, and nerves. Magnified 25 
diameters. («) part of the torn trachea; ( b ) the posterior valve; (c) the 
retractor valvulae ; (d) the circular sphincter muscle ; (e) the retractor spi- 
raculi. 
PLATE XXXVII. 
Represents the muscles, tracheae, and nervous system of the posterior part of the 
body contained in the eighth, ninth, tenth, and eleven segments, magnified. 
a. One half of the visceral surface of the eighth segment, with the muscles, nervous 
cords, and tracheae in situ. 
b. The visceral surface of the ninth segment, with the recti muscles of the right 
side of the body removed, and the recti and first and second oblique on the 
left. 
c. The ventral surface of the tenth segment, with the larger and smaller recti and 
the four oblique muscles removed to show the transverse and spiracular 
muscles, and the third rectus. 
d. The eleventh segment, containing the double ganglion and termination of the 
nervous columns. 
