380 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 19 3 8 



who had stated that light is given off by the whole body of the adult. 

 This statement of certain observers had already been refuted by some 

 of Dubois' predecessors who, Dubois considered, must have noted 

 only males. In 1854 Carpenter affirmed that the egg of Lampyris 

 emits light when within the ovary, that the freshly laid eggs are 

 luminous, and that the light does not issue from luminous material 

 adhering to the egg but from the egg itself. The eggs of the common 

 North American lampyrids (Photinus, Photuris) are, on the other 

 hand, nonluminous (Buck, personal communication). 



The larval light-organ, which is not identical with that of the adult, 

 persists and glows in the pupa and is absorbed only at the time the 

 adult emerges. Now, certain prominent biologists (such as Kuhnt, 

 1907; Pierantoni, 1914 and 1918; Buchner, 1914 and 1926) have 

 claimed that luminescence in insects is due to the presence of intra- 

 cellular symbiotic bacteria. Dubois' (1914a) numerous attempts at 

 bacterial cultures from such light organs were negative and Harvey 

 and Hall (1929) banished this notion when they found that "the adult 

 luminous organ developed perfectly from larvae having both light- 

 organs removed." The luminous granules in the photogenic cells are, 

 therefore, not due to microorganisms. Bacteria probably play a 

 nil factor in the luminosity of practically all species of living extant 

 Metazoa. Certain fishes, such as Photoblepharon and Anomalops 

 (cf. Harvey, 1921 and 1925), form the established exception to this 

 rule. It is of interest to note that only luminous bacteria, fungi, 

 and a few fish produce light continuously and that, as noted by 

 Harvey (1924), fishes which luminesce continuously have bacteria to 

 luminesce for them. If, then, continuous luminescence is a criterion 

 solely of luminous bacteria and fungi, it seems very probable that the 

 above fishes are the only luminous Metazoa which do not themselves 

 produce light but which harbor symbiotic (?) luminous bacteria. 



STIMULATION TO LUMINESCENCE 



As already explained, only luminous bacteria and fungi produce 

 fight continuously. Other forms emit light at intervals depending 

 upon the periods of stimulation. 



1. Rhythmic synchronous flashing en masse. — The phenomenon of the 

 strictly synchronous flashing of fireflies en masse, frequently observed 

 in the Tropics, has excited a considerable degree of interest and is the 

 subject of an excellent review by Buck (1938). Hence the literature 

 handled by Buck will not be dealt with here. Buck's plausible 

 theory for the phenomenon will be treated at the end of this topic in 

 connection with the significance of flashing in the economy of fireflies. 



In the journal Asia for February 1924 is an article by Carveth Wells 

 on his experiences in the Malay Archipelago (cf. Morse, 1924): 



