138 PROCEEDINGS OF THE NATIONAL MUSEUM 



Another larva was 15 mm. long, and uniformly 3 mm. broad from 

 the second thoracic to the 6th abdominal segment. The head was 

 small, the antennae relatively long, and the coxal cavities long, narrow, 

 pointed distally and white basally. The dorsal surface above the 

 luminous organs was translucent, the light evidently being visible from 

 above. Except for the structure of the terminal abdominal segment, 

 this larva might have been thought to be a larviform female. 



The spiracles on all of these larvae were on the ventral surface of 

 the lateral lobes of the abdominal segments. In the absence of rearing 

 tests, it is usually impossible to say what species a given larvae 

 represents and no attempt can be made to do so with these glow worms. 



The advice of J. W. Green, T. J. Spilman, and C. W. Sabrosky is 

 acknowledged with appreciation. 



Genus Pyractonema Solier 



Pyractonema Solier in Gay, Hist. Fis. Pol. Chile, vol. 4, Zool. pp. 445 ff., 1849. 



Diagnosis: Pyractonema is a genus of nearly or entirely nonlumi- 

 nous lampyrids at present known only from Chile and adjacent parts 

 of Argentina and possibly extending up the slopes of the Andes to 

 Bolivia and Peru. The possibility that Lucidina should be included 

 is at present ruled out. Before giving the key to the species, and their 

 descriptions, it may be well to call attention to some points of general 

 similarity which are not always repeated in the individual descrip- 

 tions, and to some of the intraspecific variations which have been 

 noted. 



The body is noticeably dorsoventrally compressed in most species, 

 sometimes so much so as to seem to leave little space for internal 

 organs. While this condition may be an artifact in closely packed 

 specimens, it appears to be a natural feature in this genus. 



The pronotum is usually semicircular or semielliptical, frequently 

 slightly prolonged apically, usually distinctly wider than long and 

 frequently markedly so in females. The base may be nearly straight 

 between the angles, slightly emarginate, or sinuate. The postero- 

 lateral angles may be posteriorly produced, salient to the lateral edges, 

 or merely rounded. There may be a median, narrow, longitudinal 

 channel or a relatively wide sulcus, or even a fine carina usually con- 

 fined to the basal half or two-thirds. The lateral margins are usually 

 reflexed, and the apical margin is slightly reflexed in most specimens. 

 The disk is usually smooth or very finely punctulate, while the re- 

 mainder of the surface is coarsely punctate, with a submarginal row 

 of large punctures. The scutellum is asymmetrically diamond- 

 shaped, the basal point being obtuse, and the apical half being longer 

 with a rounded apex. The scutellum is dark brown or black, and 

 usually hairy. The mesonotal plates are usually dull black. The 



