174 Psyche [December 



cyanide tube the phosphorescence of the ant remained undimin- 

 ished for fully five minutes, after which it decreased gradually and 

 in fifteen minutes disappeared. The light issued ventrally from 

 the last two or perhaps three abdominal segments. It was green- 

 ish yellow, and very much like that of our common eastern firefly, 

 only it was constant, not intermittent 



"We kept a sharp look-out all the way down the trail, but no 

 other specimens were found. 



"Very sincerely yours, 

 ^ "Geo. p. Engelhardt." 



The ant proves to be a worker media of Camponotus macnlatus 

 Fabr., subsp. vichnis Mayr., var. semitestacevs Emery, a form pecu- 

 liar to higher elevations in the Californian Coast Range. It is the 

 palest of several varieties of vicinus, which ranges as far east as 

 Colorado and Montana and as far south as Arizona and New 

 Mexico. The yelloAv color of the var. semitestaceus shows that it 

 is nocturnal, but my observations lead me to suspect that the 

 darker forms of vicinus have the same habit. As no ants are 

 known to possess photogenetic organs, and as C. maculotus is of 

 world-wide distribution and represented by many yellow sub- 

 species and varieties especially in North Africa and Asia Minor, 

 where any tendency to phosphorescence would certainly have been 

 seen and noted, I conclude that the specimen taken by Mr. Engel- 

 hardt must either have just fed on some phosphorescent organism 

 or have been infected with phosphorescent bacteria. Although Dr, 

 Rudolph Glaser went to some pains to section and stain the hard 

 abdomen of the specimen for me, I was unable to detect any 

 structures that might accovmt for the luminescence. This failure 

 was in great part due, in all probability, to the imperfect preser- 

 vation of the ant, which had merely been dropped into strong 

 alcohol. The problem of the source of the greenish yellow light 

 emitted by the posterior abdominal segments and witnessed by 

 Messrs. Engelhardt and Grinnell will, therefore, require fresh 

 material for its solution and must be referred to some entomologist 

 residing in California. 



