JAMES A. G. REHN 233 



males, ten females) is virtually intermediate between the typical 

 form of the species and the race here described. These speci- 

 mens are variable individually from a truly intermediate con- 

 dition to practically typical D. h. mesembrinum. From this 

 information the area of typical mesembriniun , and the points at 

 which intergradation becomes evident, can be determined. 



The present subspecies was always found on adobe soil, gen- 

 erally bare, Imt occasionally with scattered bushes and grass. 

 Double Windmill is in the middle of the broad Mara villas Valley 

 between the Santiago Mountains and the high broken countrj' 

 to the east, an extremely arid and very hot locality, an uninhab- 

 ited watering station on the Marathon-Boquillas road, about 

 forty miles south of Marathon. 



Derotmema piute new species^ (Plate XXVI, figs. 5, 6, 7 and 8; plate 

 XXVIII, figs. 9, 10 and 15. 



This striking species is related to D. delicatulum and laticinctum 

 Scudder, but is more removed from the latter than from the 

 former. There is no close relationship with D. haydenii or saus- 

 sureamim. 



From delicatulum the new species can be separated by the 

 more robust form, more distinctly vertical face with very weak 

 interantennal angle profile, proportionately broader head when 

 seen in cephalic aspect, more strongly transverse pronotum, the 

 tegmina more appreciably narrowed distad when compared with 

 the width of their proximal half, very ample anal field of tegmina, 

 slightly broader wing, shorter and more robust caudal limbs, the 

 abbreviation being shared by the tarsal joints, and the generally 

 distinct and more complete transverse banding of the tegmina 

 and caudal limbs. From laticinctum, piute can be separated by 

 the slightly more vertical face, slightly more prominent eyes, 

 which are more circular in basal outline, smoother pronotal sur- 

 face, more regularly angulatc caudal margin of pronotal disk, 

 narrower lateral lobes of the pronotum, the shorter, broader and 

 more distally narrowed tegmina, the broader wing, which has 

 the band always narrower and much weaker, the shorter and 

 more robust limbs, and, in the female sex, in the more slender 

 and straighter ovipositor jaws. 



^ Named for the Indians native to the Walker River region and adjacent 

 country of Nevada. 



TRANS. AM. ENT. SOC, XLV. 



