PHOTOGENIC ORGANS OF LAMPYRIDS 



149 



Geipel ('15) gives the structure of the light-organs some study. 

 He believes it possible that all light-organs in the Lampyridae 

 may not be derived from the fat-body. 



It is evident that the luminous organs of insects need not be 

 mesodermal in origin, for we have but to consider the very 

 efficient light-organs of the mycetophilid fly of the New Zealand 

 caves. 1 



FlCMMTtD Cut/ cvCa.. 



Moscli--- .« 



'StNocyrES 







TmcheaI CNPctlL 



.N0/hPl6MEmi) cuticuU- 



vi/mAL 



Here, curiously enough, the light-organs are a modified portion 

 of the Malpighian tubules, which of course, are ectodermal 

 (Wheeler and Williams, '15). 



STRUCTURE OF THE PHOTOGENIC ORGANS 



In all the forms of fireflies (Lampyridae) which have been 

 studied, as well as the brilliantly luminous elaterid beetle, Py- 

 rophorus noctiluca, the photogenic organs, whether of the larva, 

 pupa or adult, present the same general structure. The short 

 description which follows, together with the accompanying dia- 

 gram, text-figure 1, should give the reader some idea of their 

 makeup. The photogenic organs usually occupy a part or the 



1 This fly does not appear to be confined to New Zealand, for Morton ('91) 

 reports what seems to be the same or a very similar insect from the caves of 

 Tasmania. 



