March, 191/.] WiLLIAMS : NoRTH AMERICAN LaMPYRID.E. 17 



color, shorten up a little and assume an arcuate position. The skin 

 splits down the anterior part of the back and gradually liberates the 

 pupa. The latter is formed under the soil. 



The pupa, straightened out, measures about ii mm., and in an 

 arcuate position, 8 mm. It is depressed subcylindrical, with the ap- 

 pendages rather short and the lateral tergites only slightly drawn out 

 and hardly reflexed. It bears, especially along the edges of the seg- 

 ments, some short and quite sparse hairs. The general color is yel- 

 lowish white with a considerable suffusion of pinkish, especially 

 along the abdomen. It is much less active than the pupa of Photnris, 

 and, unlike the latter, never has a general effulgence. The larval 

 light-organs shine steadily during the pupal life but are somewhat 

 smaller and are rather more evident during the earlier than in, the 

 later pupae, where the cuticula is much pigmented. By the time that 

 the perfect insect is freed there is usually little or no luminescence 

 in the larval organ. ^ Laboratory specimens which pupated during 

 the winter were nearly all females. 



Photinus scintillans Say. 2 



This species occurs more rarely in the neighborhood of Boston 

 than consanguincus, and is found on drier, higher ground, often as- 

 sociated, though to its own detriment, with Photuris pcnnsylvanica. 

 Besides differing from its congener in its smaller size and more slen- 

 der legs, as well as paler color, the male may also be distinguished by 

 the fact that it (as well as the female) emits but a single, rather long 

 flash to the three or four flashes of the male consanguineus. The 

 female seems incapable of flight, and specimens are often met with 

 having the abdomen protruding far beyond the elytra. The semi- 

 gregarious larvae are paler and more suffused with pinkish than con- 

 sanguincus larvae. A few of the larvae were found upon the surface 

 of the ground, and several large ones, superficially buried in the light 

 soil, were taken in the evening. 

 Ellychnia corrusca Linn.3 



1 In some cases at least, there is a rather brief period in the pupal stage 

 during which neither the larval nor the adult photogenic organs glow. Such 

 a case was observed on December 14, 1913. A pupa, apparently less than a 

 day from hatching, could not by rough handling, jarring, etc., be induced to 

 give any light whatsoever, though the adult organ was plainly visible. 



2 Photinus scintillans Say, Journ. Phil. Acad. Nat. Sci., V, p. 163, 1825, 

 s Ellychnia corrusca Linn., Syst. Nat., Ed. XII, 644, 1785. 



