THE FIREFLIES Oil LIGHTNING BUGS. 827 



XVII. CHAULIOGNATHUS Hentz. '1830. (Gr., '/with exposed + 



jaws or maxilla?.") 



The species of this genus are known from all others by the 

 elongate head, and by the singular structure of the maxillary lobe, 

 which has a long, extensile, pilose, thread-like process which can be 

 pushed out and used to gather food. In this respect it is somewhat 

 similar to the tongue or proboscis of a moth or butterfly. The 

 mature beetles are said to feed solely upon the honey and pollen of 

 various flo\vers. The larva? are, however, strongly carnivorous, 

 those of our more common species being very beneficial in that they 

 feed upon the larva? of the plum curculio and other injurious forms. 

 The last ventral segment of the male is elongate-oval, convex and 

 more horn-like in texture than the other segments; the next to last 

 is broadly and deeply emarginate ; the males are also furnished with 

 a pair of slender, curved clasping organs hooked at the end and 

 fringed with hairs on the inner margin. Two species occur in 

 Indiana. 



KEY TO INDIANA SPECIES OF CHAULIOGNATHUS. 



a,. Thorax wider than long ; head black. 1572. PENNSYLVANICUS. 



aa. Thorax longer than wide ; head yellow with black spots. 



1573. MARGINATUS. 



1572 (4875). CHAULIOGNATHUS PENNSYLVANICUS DeG., Mem. Hist, des Ins.. 



IV, 1768, 78. 



Elongate, slender, parallel. Head and under parts black; 

 thorax yellow with a broad black spot on basal half ; elytra yel- 

 low with an oblong-oval blackish spot on apical third, this some- 

 times prolonged to cover two-thirds or more of the surface ; 

 ventral segments margined behind with yellow. Thorax with 

 margin rather widely flattened and reflexed. Length 9-12 mm. 

 (Fig. 322.) 



Throughout the State; common. June 30-Septem- 

 her 30. Occurs most abundantly in autumn upon the 

 flowers of goldenrod and allied plants. Riley says that the larvae 

 pass the winter in a nearly full grown stage; feed ravenously in 

 the spring and appear in the mature stage during August, Sep- 

 tember and October. I have taken them mating in Putnam County 

 on June 30, so that a few, at least, become mature by that date. 



1573 (4876). CHAULIOGNATHUS MARGINATUS Fab., Syst. Ent, 1798, 206. 

 Resembles pennsylvanicus in form, but usually smaller and more nar- 

 row. Head in great part yellow ; thorax with a broad black median stripe 

 reaching from base to apex ; blackish spot on elytra very variable in size, 



