'>"- FAMILY XXV. HTSTERIDiTO. 



e. Tibiae all dilated, the front ones with large terminal spurs. 



VI. Dendrophilis. 



ee. Middle and hind tibiae slender. 



f. Front tibiae dilated, with large terminal spur. VII. Paromalus. 

 //• Front tibia? feebly dilated, with small spur. Anapleus. 



II. Hister Linn. 1765. (L., < £ a clown or mimic") 



A very large genus, comprising about 84 of the known North 

 American species. Many of them are nominal only, being sepa- 

 rated by characters which are variable or unstable, such as the 

 length of the outer thoracic stria and the length and connection of 

 certain of the elytra! striae. Since these striae are so much used in 

 the separation of species in almost all of the genera, the following 

 brief description of them is given : 



Near each side margin of the thorax there are usually two 

 striae, known as the " outer and inner thoracic striae." The first of 

 these is often very short or wholly wanting and in the same species 

 is often variable in length. The stria? of each elytron are normally 

 nine in number, but several of them are more or less abbreviated, 

 so that the number apparent is much less. Six of these, when 

 present, are found on the disk, and, beginning near the margin, 

 are called ' 'first dorsal," ''second dorsal," etc.; the sixth one, 

 nearest the suture, being known as the "sutural." The fourth, 

 fifth and sixth are often very much abbreviated. On the margin of 

 the elytron, outside of the first dorsal, there may be three other 

 striae known as the "inner, outer and oblique subhumerals, " or if 

 only one be present, as the "subhumeral. " The two dorsal seg- 

 ments left exposed by the truncate elytra are known as the "pro- 

 pygidium" and the "pygidium." and the character of their punc- 

 tuation is also often used in the separation of species. To obviate 

 the necessity of a very long key. the species of the genus Hister 

 have been divided into six or seven groups or subgenera," four of 

 which are represented in Indiana. 



KEY TO INDIANA SUBGENERA OF HISTER. 



a. Front tibise with the tarsal groove badly defined, straight; middle and 

 hind tibiae with small spines. 



b. Mesosternum truncate or emarginate at apex; inner thoracic stria 



always present, usually entire. Subgenus I. Hister. 



1)1). Mesosternum more or less produced in front ; inner thoracic stria en- 

 tirely absent. Subgenus II. Phelister. 

 <ki. Front tibiae with the tarsal groove well defined; middle and hind tibiae 

 subdentate ; inner thoracic stria absent. 



c. Front tibiae without a tooth on the inner side near the base; spine of 



presternum flattened at apex. Subgenus III. Platysoma. 



