44 WALTER N. HESS. 



stimulus to the discharge of their flashes by the other members 

 of the group, and so bring about the flashing of the whole family." 

 From the observations and experiments performed above, it 

 seems evident that the theory of a leader is the most probable. 

 Although the author has done extensive collecting of these 

 insects during the past four summers, at no time was this phe- 

 nomenon observed on the part of any of our other native species. 



The small, smooth, spherical eggs are laid on the soil at the 

 base of the roots of grass and moss where they hatch in about 

 twenty to twenty-two days. The larvae are slender, elongate, 

 and of a rather uniform dark grayish color. They were found 

 chiefly a short distance below the surface of the soil, though a 

 few specimens were taken at the surface. It seems, however, 

 that its habitat is subterranean, rather than terrestrial, in con- 

 trast to that of Photurus pennsylvanica. They are predacious, 

 feeding on snails, etc., similar to the other species studied. 



It seems very evident that the insects have a two-year life 

 cycle, as both mature and half-grown larvae were taken at the 

 time of pupation. 



Pupation takes place in the soil near the surface of the ground. 

 Here the mature larvae excavate a little chamber, in which the 

 period of transformation is spent. After transforming to pupae 

 they lie on their backs in an arcuate position. In this condition 

 they measure about seven mm., but when straightened out they 

 are about nine mm. long. The pupae are yellowish white in 

 color with the pleural regions somewhat pinkish. The pupal 

 period lasts from twelve to fifteen days. 



Photinus scintillans Say. 



The adult beetle of this species is rather elongate and slender'^ 

 somewhat flattened with the head completely covered by the 

 prothorax. The antennae are eleven-segmented, the second seg- 

 ment being short and transverse. The prothorax is rounded an- 

 teriorly and along the sides, truncate behind with the angles 

 acute. The elytra have wide side margins. The head is black. 

 The prothorax is pale yellow, except the small black median bar 

 on its central posterior half, which is bordered with pink. The 

 elytra are pale yellow, except the side and suture margins which 



