THE FIREFLIES OR LIGHTNING BUGS. 



821 



Marshall and Orange counties; rare. May 28-June 10. A spe- 

 cies of wide distribution, but everywhere much less common than 

 angulata. 



15G] (4826). Pyractomena li cifera Melsh.. Proe. Phil. Acad. Nat. Sci., 

 II, 1845, 304. 



Elongate, narrow, parallel. Colors as in angulata except that the dusky 

 spot on margins of thorax is mure distinct, and occurs only on middle third 

 of the margin. Yellow margin of elytra much narrower and more parallel 

 than in angulata. Male with ventral segments 1-4 piceous, seventh with 

 a piceous spot ; female with fifth and sixth also piceous at middle. Length 

 8-14 mm. 



Lake and Kosciusko counties; scarce. June 3-? June 24. Prob- 

 ably throughout the northern half of State. 



XI. Photintjs Lap. 1833. (Gr., "shining.") 



Hood-like thorax not at all carinate, usually slightly grooved 

 and more obtusely rounded in front. The light organs are always 

 the larger in the male, where they occupy all the ventral segments 

 behind the third or fourth and are accompanied by stigmatic pores 

 on the fifth and sixth segments. In the female they occur on the 

 middle part of the ventral segments, but the stigma-like impres- 

 sions are barely or not visible. Five have been taken in Indiana, 

 while one other perhaps occurs. 



KEY TO INDIANA SPECIES OF PHOTINUS. 



a. Fourth ventral segment dark. 



/>. Thorax with a black stripe and two roseate spots ; elytra with wide 

 side margins. 1562. consanguineus. 



hb. Thorax with a dusky cloud or black spot; elytra with narrow side 

 margins : form more narrow. 

 c. Thorax with hind angles acute, somewhat produced, its disk 

 smooth, margins punctate. 1563. ardens. 



cc. Thorax with hind angles not produced, its disk finely, margins 

 densely and rather coarsely, punctate. punctulatus. 

 an. Fourth ventral segment pale, at least in part. 



(1. Large species (9 or more mm.) ; disk of thorax roseate with a large 

 black spot ; ventral impressions of male very distinct. 



1564. PYRAEIS. 



(1(1. Small species (less than S mm.) ; ventral impressions of male obso- 

 lete. 



c. Elytra pale, widely margined ; female with long elytra and wings. 



1565. MARGTNELLUS . 



cc. Elytra dusky with pale margins, narrowly margined; female with- 

 out wings, elytra short, widely separated at suture. 



1566. SCINTILEANS. 



