CAROTINOIDS IN INVERTEBRATES 161 



ously, the whole matter of the grasshopper and locust pigments needs 

 further study. 



Acerata. The animals in this group are not, strictly speaking, 

 insects, but are a lower order midway l>et \\ecn insects and Crustacea. 

 11 rim (1892) examined the red pigment in the larvae of one species, 

 namely Trombidium, or common red mite. He found it to be soluble 

 in the fat solvents with a red color and that it gave the lipochrome 

 reaction with the concentrated acids. Its possible relation to the 

 carotinoids is thus indicated. 



Carotinoids in Crustacea 



Pigmentation among the Crustacea is characterized both by the 

 variety of colors exhibited and by their brilliancy. The various colors 

 found, including blue, green, and various shades of orange, red and 

 brown, are more frequently found singly on a species, rather than 

 mixed to give varied-colored effects. Examples of brilliant single 

 colors are seen in the higher and lower crabs, the lobster, and the cray- 

 fish. Instances of varied-colored forms are the prawns, such as 

 Hippolyte varians, Leander serrator, and the wrasse, Grenilabrus 

 melops. These latter species have various pigments deposited in 

 chromatophores, whose expansion and contraction under the influence 

 of various agents, brings about some remarkable color changes in the 

 animals. Contrary to the situation found in many of the higher 

 animals the blue and green colors encountered in Crustacea are not 

 structural, but are due to pigments whose relation to the red lipo- 

 chrome so common to these animals is so intimate and yet so fugi- 

 tive, that its exact nature has never been discovered. 



From an historical point of view Pouchet (1876) seems to have first 

 described the properties of red and yellow ether soluble pigments in 

 the hypodermis, eggs and ovaries of the lobster and other Crustacea. 

 Both pigments dissolved in concentrated H 2 S0 4 with a color change 

 from green to blue to violet. The pigments differed, however, in that 

 the yellow one was soluble in alcohol, but the red one was not. The 

 red pigment was obtained in crystalline form, the crystals being violet 

 colored with a metallic reflection. Jolyet and Regnard (1877) noted 

 the presence of a yellow, ether soluble pigment in crab's blood, and 

 Frcderiquc (1885) a similar red pigment in the blood plasma of the 

 lobster. Moseley (1877) was the first to name the red pigment, call- 

 ing it crustaceorubin. He also noticed its single absorption band in 



