THE FIREFLIES OR LIGHTNING BUGS. 



837 



at present unrecognized by entomologists, but which is probably 

 this species. He gives the length as less than one-fourth of an inch 

 and there are some minor details of color which do not agree with 

 the specimens at hand. 



XXII. Ditemnus Lec. 1861. (Gr., "twice + to cut or split." 



Antenna? stout, compressed and serrate; sides of thorax lobed 

 in such a manner as to present two notches, one near the tip formed 

 by the thickened apical margin, the other between two narrow lobes 

 or processes which extend outward near the base. In our species 

 the base of thorax is strongly margined and its disk excavated. 



KEY TO INDIANA SPECIES OF DITEMNUS. 



a. Hind lobe at side of thorax very little wider than the one before it; 

 smaller, not over 3.5 mm. 159S. bidentatus. 



aa. Hind lobe at side of thorax more than twice the width of the one be- 

 fore it; larger, 4.5-5.5 mm. 1599. latilobus. 



1598 (4969). Ditemnus bidentatus Say, Jonrn. Phil. Acad. Xat. Sci., V. 



1825. 169 ; ibid. II, 278. 

 Oblong, sparsely clothed with grayish pubescence. Black; thorax dull 

 yellow. Second joint of antennae not dilated, about one-third as long as 

 third, which is equal to fourth. Thorax slightly wider than long, the ap- 

 ical lobe of sides well defined, middle and hind lobes narrow, parallel. 

 Length 3.5 mm. 



Lake. Laporte, Spencer and Dubois counties: scarce. May 12- 

 July 25. Occurs on low herbs along roadsides. 



1599 ( ). Ditemnus latilobus sp. nov. 



Elongate-oblong. Black or pic- 



eous. feebly shining ; thorax reddish- 

 yellow. Second joint of antenna? 

 rounded, not pubescent, less than 

 one-fourth the length of third, the 

 latter equal to fourth. Thorax one- 

 third wider than long, the base more 

 strongly margined than in bidenta- 

 tus; basal side lobes prominent, the 

 front one narrow, its apical half a 

 little wider and bent slightly down- 

 ward and backward, the tip Oblique- Fig. 32(3. LL.e shows natural length. (Original.) 



ly truncate ; the hind one more than 



twice as broad and a little shorter, concave, its apex rounded and bent for- 

 ward or slightly toothed so as to touch the front lobe, leaving only a small 

 rounded notch between the two, its hind margin overlapped at base by the 

 hind angles of thorax ; median impression of disk distinctly larger than in 

 bidentatus, its limits marked by four slight tubercles, its margins indistinct. 

 Elytra finely scabrous, sparsely and very finely pubescent. Length 4.5- 

 5.5 mm. (Fig. 326.) 



