218 TERTIARY INSECTS OP NORTH AMERICA. 



HOMCEOGAMIA VENTRIOSA. 



PI. 17, Fig. 8. 

 Ilnmiroi/ntiiin nnlrtoftiis ScuiUI., Hull. U. S. Geol. Geogr. Surv. Terr., I, p. 447 (1876). 



The remains upon which this species is based consist of the apical por- 

 tion of the ventral surface of an abdomen. Five segments are seen in nat- 

 ural juxtaposition, showing- that the apical portion of the abdomen was very 

 regularly rounded, almost exactly semicircular, the terminal segment pre- 

 senting no break in the regular continuity of the curve. This segment was 

 ample, broader than long, and probably neither very tumid nor greatly 

 keeled; for in the present perfectly flattened condition of the fossil there is 

 neither break nor folding of the integument; the two segments following 

 this are very strongly arched (the penultimate being semicircular) and 

 greatly contracted at the middle, so that this portion is not less than half as 

 long as the lateral parts ; the anterior border of the antepenultimate segment 

 is straight along the middle ; the segment anterior to this is also arched, 

 though not strongly, is oppositely sinuate (as are to a less extent the seg- 

 ments posterior to it), and also much contracted in the middle, so as to be 

 less than half as long as at the sides; while its predecessor is slightly arcu- 

 ate in the opposite direction (probably exactly transverse in life), and equal 

 or subequal throughout. All the segments are uniformly, rather abundantly, 

 and very delicately granulate throughout. There is no trace of cerci, but 

 the place where they should occur is too broken to assert that they did not 

 exist externally; still the conformation of this region would lead one to sup- 

 pose that they must have been excessively minute, and perhaps altogether 

 concealed within the segments, as in Cryptocercus Scudd. 



Length of fragment, S"""; width of same, 12.25"""; length of terminal 

 segment, 3.6 mm ; width of same, 6.3"""; length of antepenultimate segment 

 in the middle, 0.6'"" 1 ; at the sides, l.S.V 1 "". 



I have referred this species to Homoeogamia with some doubt ; on some 

 accounts it would seem to be more nearly allied to I'olyphaga : but as the 

 specimen is too fragmentary to allow of more exact determination I have 

 preferred to place it in the New World genus rather than in its close ally, 

 which is restricted to the Old World. Cockroaches of such large size are 

 indigenous in warm climates only. 



Florissant. One specimen, Mr. T. L. Mead, No. <S. 



