1835.] 



Colouring of Phytophagous Larvce. 



285 



The spectrum showed the band in the red from 65 - 5 — 68*5, while 

 the bine was cnt off at 50, darkened to 52. The band was very sharp 

 and distinct. 



The blood of this individual was also examined, and it was of the 

 same colour as the last, and possessed the same spectroscopic charac- 

 teristics. This observation upon the green fluid from this digestive 

 tract is important, because it serves to identify the chlorophyll in the 

 blood with that taken in as food. It is likely, however, that a greater 

 thickness of fluid and the use of sunlight would bring out some 

 differences between the derived pigment dissolved in the digestive 

 secretions, and that united with a proteid in the blood. It is also 

 noteworthy that the chlorophyll was present in solution. 



All the observations hitherto recorded were made with the illu- 

 mination of a paraffin lamp. Early in January I found how much 

 more could be seen in these spectra at th^ violet end by the use 

 of bright sunlight. About the middle of January the more con- 

 centrated of the two specimens of green blood in sealed tubes was 

 examined by sunlight, and the spectrum mapped (see Chart, 

 Spectrum 1). The band in the red, reaching from 64'5 — 68, was 

 very black, except at the edges. When this band was most 

 distinct and clear the violet end was absorbed to 51, darkened 

 to 52. On opening the slit a little, the blue came through (though 

 dimmed) at 48, the violet end being absorbed at 43. When the 

 slit was very narrow, traces of another band, from 59*5 — 61*5, were 

 faintly seen. The spectrum was unchanged at the end of March, 

 although the blood had been exposed to light for a considerable time. 

 The two chief bands and the absorption of the violet end were also 

 seen in the blood of a living larva by passing the light through one 

 of the claspers. 



(&.) The Pupa of Pygasra Bucephalus. — The blood of this species is of 

 a very bright and beautiful green colour. I have examined it on a great 

 many occasions, with all conditions of daylight. In the Chart, Spec- 

 trum 3, is shown the spectrum of the thickness of 235 mm. examined 

 with bright sunlight. The characteristic band in the red ends sharply 

 at 71, gradually at about 64*5, passing into a lesser absorption of the 

 red, which is continuous with the second band, extending from about 58 

 — 60*5, but with very indistinct limits. When these appearances are 

 best seen the violet end is completely absorbed to 52, darkened to 52*5. 

 On opening the slit a little, the dimmed blue comes through from 48 

 — 42. The band in the blue now sharply ends at 52, gradually at 48. 

 Diminishing the thickness of the blood to 8 mm. produces nearly the 

 same spectrum, the band in the red being a little narrower, while the 

 band at D cannot be detected. On diminishing the thickness still 

 further to 1 mm., another band appears in the violet. The spectrum 

 is as follows : — The characteristic band from 65 — 70, the chief band 



