Mr. Macartney's Observations 
.tinal parts. Both these figures are copied from the original 
drawings, in the possession of the Right Hon. £ Joseph 
Banks. 
Fig. 13. Is an enlarged view of the inferior a.a,V a. , ' the 
abdomen of the lampyris lucida, after the integument - d 
been removed, a a a represent the three rear •• •/. a i mi nous 
substance which are applied to the three last rings of the 
abdomen, b b b the arrangement of cellular or interstitial 
substance on the other abdominal rings, which gives the pale 
colour to the whole belly of this insect. 
Fig. 14. Represents the common glow-worm, with the pos- 
terior portion of the back cut away to expose the sacs of lu- 
minous matter in situ on the last ring of the belly, a indicates 
the sac of one side ; the intestine is seen to lie between 
them. 
Fig. 15 and 16. Are the sacs of the glow-worm prodigiously 
magnified to shew r their structure. Fig. 16’ is cut open to ex- 
pose the luminous matter it contains : the coat of the sac is still 
seen to preserve its figure. 
Fig. iy. Is the elater noctilucus, with the shell of the cor- 
celet removed on one side, by which the organ of light is 
uncovered, a the yellow transparent spot of the corcelet. b the 
oval mass of luminous substance surrounded by an irradiation 
of the interstitial substance, c the ends of the muscles which 
were on the inside of the corcelet. 
Fig. 18. Is the posterior angle of the corcelet of the elater 
noctilucus magnified, a the radiated appearance which the 
interstitial substance has round the oval mass of luminous 
matter. This mass is seen to consist of a number of smaller 
parts, b shews the appearance of the interstitial substance. 
