]^48 [December, 



ON THE LL'MINOUS LAEVIFORM FEMALES OF THE PEJENQOBIFI. 



BY PROF. C. V. RILEY, M.A., Ph.D." 



Certain interesting phosphorescent Coleopterous larvaa, reaching 

 2 1 to 3 inches in length, had been well known to occur in America 

 ever since Baron Osten Sacken first minutely described them in 1862, 

 and discussed their affinities between the Elateridce, Lampyridee, and 

 TeleplioridcB. 



The structural characters most peculiar to them are, the horizontal 

 head, protruding labium ; falciform, grooved, and untoothed mandibles 

 inserted on sides of head ; certain ventral conchoid depressions ; 

 minute dorsal stigma-like glands opening by a crescent slit between 

 the joints ; and the lateral spiracles. 



The great interest attaching to these larvae is not so much in their 

 luminosity, as in the fact that a portion of them are now known to be 

 true and perfect females of Phengodini, w^hich have, until recently, 

 been represented in Coleopterological collections in the male sex only. 

 The history of this discovery furnished another instance of simul- 

 taneous and independent observations on the same point in different 

 parts of the world. 



In 1883, in connection with Mr. E. A. Schwarz, I had arrived at 

 this conclusion in Washington, with the intention of some time pub- 

 lishing the facts upon which it was based, when the same conclusion 

 ■was being verified by Dr. Hieronymus, of Cordova, and the announce- 

 ment anticipated by him, and by Dr. Haase, in 1885. 



I have been accumulating material since 1869, with notes, and 

 have critically examined in all some thirty different lots in my own 

 collection, at the National Museum, and in the collections at Phila- 

 delphia, Boston, and Cambridge. These all belong to Pliengodes and 

 ZarMpis, with the exception, perhaps, of Osten Sacken's No. 2, which 

 may be Spathizus. The differences between the larva proper and the 

 adult female are so slight that it were difficult to separate them with- 

 out some absolute index. I have been fortunate in obtaining 

 undoubted females, coupled with their males, of Phengodes laticollis 

 and Zarliipis Piversii ; and in both genera there were absolutely no 

 other structural differences than the somewhat shorter (relatively) 

 mandibles and tarsal claw in the adult. 



In reference to life-history, the food of ZarMpis is known to be 

 Myriapods ; the eggs in both genera are spherical, translucent, and 



* Abstract of a Paper read before the British Association for the Advancement of Science, at 

 Manchester, couinjunicated by the Author. 



