INSECTA. 149 



Penultimate-joint of tarsi bilobed .... TETRAONYX. 

 Penultimate joint of tarsi cylindrical. 



Lower portion of claws equal to upper. 



Anterior thighs with a sericeous* hairy spot. 

 Second joint of antennae equal to half 



the third PLEUROPOMPHA. 



Second joint of antennas very short . EPIOAUTA. 

 Anterior thighs glabrous, no sericeous spot. 



Antennae filiform, outer joints cylindrical PYROTA. 

 Antenna? thicker externally, outer joints 

 rounded. 



Labrum deeply emarginate . . POMPHOFCEA. 

 Labrum slightly emarginate . . LYTTA. 

 Lower portion of claws shorter than upper. 



Labrum not emarginate, body pubescent . CALOSPASTA. 

 Labrum emarginate, body not pubescent . TEGRODERA. 

 By the above table of characters, all the genera from our own and neigh- 

 boring countries may be recognized. Lytta is equivalent to Gantharis of 

 older authors, the latter name having been dropped on account of the confu- 

 sion of species adopted at various times as its type. As several of the above 

 genera are rare, even in the cabinets of entomologists, it would be well to 

 notice from among them various species capable of being used in medicine 

 as a substitute for the Lytta vesicatoria of Europe. 



Macrobasis fdbricii is our common American species, nearly one-half inch 

 long, found on various plants during the early summer months, in all parts of 

 the country. The color is ashy gray with darker antennas. 



H. lateicorm's is a large Texan species, occurring in very great abundance 

 when found. It is of a light ashy-gray color, with reddish-brown antennas, 

 the first joint being (in the males) large and broad. 



Epicauta vitatta is our common potato fly, and occurs abundantly during 

 June and July on the potato and tomato plants. It is an elongated insect, 

 black in color, with yellowish stripes on the thorax and elytra. This insect 

 must not be confounded with the potato bug of the West, a short, robust 

 insect of a different group and not at all vesicant. 



Epicauta Pennsylvania is smaller than the above and totally black. 

 Epicauta ferruyinea and maculata are found abundantly in the plains of 

 the West ; the latter is gray, with black spots, the former ferruginous in 

 color ; both are small. 



Pyrota contains many moderate or large species, characterized by a yel- 

 low body and legs ; the elytra have large spots or bands of black. These 

 all occur in our Southern States and have good vesicatory power. 



Pomphopcea contains several species, occurring rarely in abundance. 

 They all have aeneous elytra and yellow legs. One species is occasionally 



* Sericeous covered with a fine silken recumbent pubescence. 



