OEDEMERIDAE FROM TEXAS — ARNETT 53 



(LeConte). The darker central spot on the head is confined in most 

 specimens to the interocular area, only rarely extending over a larger 

 area. The paler prothorax varies considerably from specimen to 

 specimen. In a few the prothorax is as dark as the elytra. One 

 of the ways to distinguish this species from Oxycopis mariae (Arnett) 



1.5 2.0 2.5 3.0 



Figure 3. — Interocular distance ratio of Oxycopis howdeni, new species, and two populations 

 of 0. mariae Arnett (horizontal line = range of variation; vertical line = mean; black part 

 of bar = two standard errors of standard deviation on either side of mean; one-half of 

 each black bar plus white bar at either end =one standard deviation on either side of mean). 



is by the wider interocular distance. The variation of this distance 

 was studied statistically and is found to be significant. The sta- 

 tistical differences between 0. howdeni and 0. mariae, so far as this 

 character is concerned, are compared in figure 3. 



Oxacis pallida (LeConte) 



Some of the 26 specimens of this species were taken on candelilla 

 (Euphorbia antisyphilitica) (pi. 1, bottom) and others at light at the 

 Boquillas area. May 17-23. This species is very common throughout 

 the arid regions of the United States. It also occurs in Sonora and 

 probably in Chihuahua. 



Oxacis subfusca Horn 



Plate 2 



Only one specimen of this species was collected. It was taken at 

 Boquillas, May 23. The species is usually abundant on prickly poppy 

 blossoms in other areas during late July and August, so perhaps more 

 may be found later in the season. 



Oxacis angustata Champion 



Although this species was described from four specimens taken at 

 Tehuacan, Puebla, Mexico, I have seen it from Chihuahua and Tamau- 

 lipas. It agrees very well with the description and type of the species. 

 Eighty-five specimens were taken as follows: Hot Springs, 1900 ft., 

 May 1-29; Boquillas, 1850 ft.. May 13; Oak Spring, 3000 ft.. May 24; 

 Panther Junction, 4000 ft.. May 28; and Tornillo Flat, 3200 ft.. 

 May 12. 



