174 



REPORT OF STATE GEOLOGIST. 



said that it occurs at every horizon where insects have been found in 

 any numbers; in no group whatever can the changes wrought by time 

 be so carefully and completely studied as here; none other has fur- 

 nished more important evidence concerning the phylogeny of in- 

 sects." 



The Blattidffi are pre-eminently tropical insects, and though abun- 

 dantly represented in individuals, the number of species inhabiting 

 the United States is comparatively few, but 34 being listed in Scud- 

 der's Catalogue. These are divided among seven sub-families and 

 eighteen genera. Aside from two or three sub-tropical species which 

 are often introduced in bananas and other fruit, but which soon die, 

 and are not, therefore, considered in the ])rescnt paper, nine species 

 have been taken in Indiana. These represent but two of the sub- 



Fig. 23. Nymph of Nyctohora holoserieea Klug. One of the more common tropical 

 roachei introduced on fruit." (After Lugger.) 



families and five of the genera, belonging to that division of the fam- 

 ily in which all the femora, or at least the middle and hind pair are 

 spined on the under side. These sub-families may be separated by 

 the following table: 



A SYNOPSIS OF THE SUB-FAMILIES OF 15LATTID-E KNOWN TO OCCUR IN 



INDIANA. 



a. Last ventral segment of the female abdomen plane, not compre.ssed 

 and not divided; fore femora rarely armed beneath on the inner 

 margin with many distinct spines; if so armed, then the sub- 

 genital styles arc uiic<inal. or one is wanting. . . . .Rt.attin.t;, p. 17.5 



'•'Nymphs of this pulj-tropical roach liave hecn taken in Indianapolis and Terro Haute 

 A mature male wai sent me from Mt. Carmcl, Illinois, by Dr. J. Schnock. It was an inch 

 and a fourth in length, a uniform dark brown in color, with numerous small hairs on the 

 pronotum and tegmina. 



