DR. C. A. MAC MUNN ON MYOH2EMATIN AND THE HISTOH2EMATINS. 281 
Fraunhofer line D, two others narrow and sharp, of which the second is darker than 
the first, between D and E, and generally two others nearer the violet (spectrum 10, 
Chart III.). The first three in the case of Geotrupes stercorarius read :— 
1st hand 
2nd band 
3rd band 
4th band 
X 613 to X 593, 
X 567-5 „ X 561-5, 
X 554-5 „ X 546, 
X 532 ,, X 511’5 (about). 
In the alar and other voluntary muscles of other insects (and I have now examined 
a great number) myohsematin is the pigment to which they owe their reddish-yellow 
or yellow colour. I do not think it necessary to give a drawing of the spectrum of 
myohsematin in each case, as its bands always occur in the same part of the spectrum; 
besides anyone who possesses a microspectroscope can easily verify the truth of my 
statements for himself. 
In Hyclrophilus piceus and Dyticus marginalis, as already stated, the myohaematin 
bands are seen with great distinctness, and in Hydrophilus early in 1883 I measured 
the bands in wave-lengths with the following result:— 
1st band 
2nd band 
3rd band 
X 613 to X 593 
X569 ,, X563 h Approximate. 
X 557 „ X 548-5J 
The other bands could not be accurately determined. By heating this muscle in 
rectified spirit and caustic potash I obtained a small quantity of a yellow solution 
showing some feeble shading in green, and on adding sulphide of ammonium two bands 
like those of hsemochromogen came into view, but much nearer violet than those of 
hsemochromogen, thus the first extended from about X 557 to X 548"5, and evidently 
corresponded to the third band seen in the muscle. I would call attention to this fact, 
because a similar spectrum is seen in some insect muscles without any treatment, and 
it was also seen in a solution of isolated myohsematin from vertebrates obtained by 
digesting the blood-free muscle in pepsine and water.* This kind of modified myo¬ 
hsematin was met with in Lucanus cervus, as shown in spectrum 11, Chart III., also 
in some specimens of Periplanetci orientalis , in Bombus terrestris, and in Apis mellijica, 
in all of which species the unmodified myohsematin also is found. In Lucanus 
these hands of changed myohsematin read : — 
1st band ... X 557 to X 548'5, 
2nd band ... X 532 „ X 516 (?). 
and therefore are placed in the same part of the spectrum as the third and fourth (?) 
bands of the normal myohsematin spectrum. 
* See Chart IV., and cf. with spectrum of muscle of Lucanus, &c. 
MDCCCLXXXVJ. 2 o 
