228 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
colors of many Lepidopterous larvee and pup were due to chlorophyll 
and xanthophyll derived from the leaves of their food plants. The 
hemolymph is acid to litmus, and I find that it actually contains a 
large amount of orthophosphoric acid (ammonium molybdate test). Mr. 
George Oenslager has kindly determined the mineral bases of the hemo- 
lywph for me, and finds them to be iron, potassium, and sodium. The 
iron is present in considerable quantity. 
Although the freshly obtained hemolymph is a clear opalescent amber- 
yellow fluid, it soon becomes turbid upon exposure to the air, and in less 
than half an hour after removal from the chrysalis becomes opaque, and 
drab or greenish drab in color. It is interesting to note that the drab 
color assumed by the dried hemolymph from the pupa of Callosamia 
promethea is very similar to the drab of the outer edges of the mature 
wings. In the case of Philosamia cynthia, also, the haemolymph dries 
into a greenish drab color, which is strikingly similar to the principal 
color of the moth’s wings. In the case of Samia cecropia, however, the 
hzemolymph becomes rather greener in color than the drab of the mature 
wings. 
This curious change in color which the hemolymph exhibits upon 
exposure to the air is probably not a simple process of oxidation, for it 
will take place in an atmosphere of hydrogen, although rather more 
slowly than in the air. An atmosphere of CO,, however, practically 
prevents it, for after remaining for 48 hours in this gas, the haemolymph 
shows only faint traces of a drab-colored clot around the edges of the 
liquid, which remains clear and amber-yellow in color. If the hamo- 
lymph be sealed up air-tight in glass tubes, it will retain its clear amber- 
yellow color indefinitely. When the newly extracted clear amber-colored 
hemolymph is heated to 54° C., it begins to congeal, and at temperatures 
above 63°C. it rapidly solidifies into a chrome-yellow colored mass. In 
this condition it will keep indefinitely, always retaining its original 
chrome-yellow color. In like manner congelation can be produced in 
hemolymph that has become drab by exposure to the air, only in this 
case the congealed mass is drab, not chrome-yellow in color. 
If, in accordance with my hypothesis, it be true that the colors of the 
mature wing are derived, by various chemical processes, from the heemo- 
lymph of the pupa, then one ought to be able to manufacture various 
colors from the hemolymph by means of chemical reagents. Also, if the 
color so manufactured be similar to some color upon the mature wing, it 
may be expected to present reactions to chemical reagents similar to 
those of the color on the wing. As far as my rather limited experiments 
