178 BULLETIN 190, UNITED STATES NATIONAL MUSEUM 



side the laboratory, attracted a male before the camera could be set and 

 a dozen or more followed soon afterward. I have had no success in a 

 similar experiment with Aegeria apijormis. 



Critical examination of the ample material that is available shows no 

 structural differences to warrant specific separation of tibialis and pacifica. 

 Color variations are not restricted geographically but occur more or less 

 throughout the transcontinental range of the species, the usual light colors 

 darkening increasingly northward and at higher elevations. 



Beutenmiiller recognized two North American species under Aegeria, 

 tibialis and pacifica. He treated minimum as a synonym of tibialis and 

 calif ornicum as a synonym of pacifica. His illustrations of tibialis do 

 not conform with Harris's description, being much too dark. The male 

 figure represents an almost black specimen marked narrowly with yellow 

 on the thorax and abdomen. Probably it was discolored with grease. 

 The female figure is a dark color variety, which is treated in the present 

 paper under the name melanojormis. The typical form is predominantly 

 yellow marked with black, and not predominantly black marked with 

 yellow. In addition, Beutenmiiller illustrated (pi. 2)i, fig. 13) as an 

 unnamed variety a female from Colorado, an unusually fine, large, and 

 well-marked example of pacifica, a name retained here for the form most 

 representative of Rocky Mountain and Pacific coast regions. Cockerell 

 refers to this illustration in his description of Aegeria tibialis var. dyari, 

 and the variety anonyma Strand also is based on the same illustration. 



Types of the following are in the United States National Museum : 

 Trochilium pacificiim Hy. Edwards, female, Washington Territory, 1881 ; 

 T. calijornicum Neumoegen, female, California, 1891 ; T. minimum 

 Neumoegen, male, Colorado, 1891 ; Aegeria tibialis var. dyari Cockerell, 

 female, New Mexico, 1906. The type specimens are old, faded, and 

 abraded, but there can be no doubt that all are conspecific. Color varia- 

 tions are not clean-cut or geographically restricted. In addition to the 

 typical form two varieties are recognized. 



AEGERIA TIBIALIS MELANOFORMIS, new variety 



Plate 30, Figure 174 



Male. — Head with a yellow brush on top. Thorax deep brown-black, 

 a thin yellow stripe on inner side of tegula and a broader yellow mark on 

 prothorax extending obliquely to beneath wing base, which also is spotted 

 with yellow above ; metathorax tufted with yellow at the sides. Abdomen 

 brown-black, all segments narrowly banded with a pale yellow, most 

 broadly on segment 3, above and beneath ; a row of black spots at the sides 

 on segments 3, 4, 5, and 6; anal tuft a short, stiff brush, orange-yellow 

 and brown. Wings with costa, discal mark, veins, and margins brown- 

 black ; beneath shaded with yellow basally. 



