166 CARNEGIE INSTITUTION OF WASHINGTON. 



Cypridina hilgendorfii. Lund had described such a green-hght form from 

 Jamaica, and it was desired to find a supply nearer home. Such an animal was 

 found through the kind help of Dr. Louis Mowbray, director of the Miami 

 Aquarium, and seems to be a more or less pelagic species which comes on the 

 coast in laige quantities at intervals. Arrangements are being made to secure 

 the material to be used as stated. Many interesting notes were made on other 

 luminous forms, but the fishes were not found with the apparatus at our 

 command. 



Studies on the Pieridce, by John H. Gerould. 



The discovery in 1920 and 1921 of blue-green and ohve-green mutations in 

 caterpillars of Colias philodice, involving changes in the hemolymph, in eye- 

 color, and other characters of the prospective butterfly, led in 1922 to a 

 spectroscopic study of the blood of caterpillars. With the assistance of Dr. 

 J. W. Tanch, of the Department of Physics of Dartmouth College, an expert 

 in spectroscopy, photographs have been taken showing the absorption effects 

 produced by the hemolymph of the leaf-eating caterpillars of various moths 

 and butterflies, by solutions of chlorophyl and xanthophyl, and by mammahan 

 blood. Attention is being given to differences existing between different 

 species, between the different sexes of the same species, and particularly to the 

 relation of chlorophyl to green and yellow blood-pigments in leaf-eating 

 caterpillars. That these pigments are derived from the chlorophyl of the food 

 with no considerable change was assumed in my paper on the blue-green 

 caterpillar (Jour. Exper. Zool., vol. 34, pp. 385-412), on the basis of the early 

 researches of Poulton and the more recent investigations of Geyer. Actual 

 photographs of the absorption spectra upon which these conclusions were 

 based have never been published, but improved instruments and methods now 

 make it possible to prepare for pubhcation excellent detailed spectrograms. 



Adverse climatic conditions in the winter of 1920-21 (extraordinary dryness 

 of the soil and, possibly, the remarkably long periods of intense cold) destroyed 

 my selected stocks of hibernating blue-green and olive-green caterpillars before 

 spectroscopic tests could be applied to their blood, and temporarily almost 

 exterminated in this region the species (Colias philodice) to which they belong. 

 But stock of Colias eurytheme var. eriphyle, the yellow western variety of the 

 "orange-sulphur" butterfly, sent me by Professor P. W. Whiting from 

 Nebraska and Wyoming, is being inbred in search of similar mutations. 



Breeding experiments with a cabbage butterfly, Pieris napi, represented in 

 America by the variety oleracea, the "gray-veined white," have been started 

 in collaboration with Professor J. W. H. Harrison, of Armstrong College, 

 Newcastle-upon-Tyne, England. A cross-mating between Pieris rapce 9 

 and P. napi var. oleracea cf has been obtained, but efforts to produce the 

 reciprocal cross have not been successful. 



Mr. Lloyd C. Fogg, a graduate student, has rendered excellent assistance 

 in this work. 



Report of Investigations on the Production of Light by Animals, 



by E. Newton Harvey. 

 Research was continued on the chemical processes underlying the produc- 

 tion of light by organisms. Specimens of Cypridina hilgendorfii, dried under 

 the direction of Professor Chiomatsu Ishikawa, of the Imperial University 



