MORGAN HEBARD 169 



ference is however well known to be usually an utterly unsafe 

 feature except in conjunction with other more stable characters 

 and we consequently repudiated it at that time. 



In associating the forms nearer oregonensis even more mis- 

 leading were the few (and well known to be unsatisfactory) 

 external features by which marshallii could be separated from 

 oregonensis. The average slightly narrower male supra-anal 

 plate and average smaller size of the former were the strongest 

 reasons we had for giving that insect even racial recognition, 

 and the Wyoming series which were smaller than is usual for 

 oregonensis appeared to indicate intergradation. As a matter 

 of fact large series from Colorado and Utah are now found to 

 have a penis sufficiently differently constructed to warrant 

 specific separation and our Wyoming material (all from the 

 northern portions of that State) is as clearly representative of 

 oregonensis. Though we have no males from central or southern 

 Wyoming, our knowledge of the distribution of other species in 

 that State enables us to predict that oregonensis will probably 

 be found in the mountains at sufficient elevation south to central 

 eastern and southwestern Wyoming, while that species is as prob- 

 ably supplanted by marshallii in similar environment throughout 

 southeastern Wyoming. The distribution westward and inter- 

 gradation between typical marshallii and marshallii ascensor can 

 only be definitely charted when material of the species from a 

 number of stations in the Uinta Mountains has been secured, 

 though we believe that intergradation will be found in the moun- 

 tains in the vicinity of the Green River in extreme northwestern 

 Colorado and northeastern Utah. 



It is particularly interesting to note that the ventral surfaces 

 of the caudal femora are dull buff, tinged with orange only in 

 intensive specimens of some series, in all of the species of this 

 group except in indigens. These areas are rich reddish or orange 

 in all well preserved specimens of the races of that species except 

 in decidedly recessive or badly discolored specimens. 2 



2 Such unfortunately is the case in the type of indigens indigens, which 

 though dark in general coloration, has the ventral surfaces of the caudal 

 femora dirty buff, this plainly the result of very poor preservation. 



TRANS. AM. ENT. SOC, LXII. 



