116 BULLETIN 143, UNITED STATES NATIONAL MUSEUM 



that agenar Fox is the male. Vesta occurs all through the Northern 

 States and Canada as far west as British Columbia and also in the 

 Southern States from the Atlantic coast to Arizona, and is the only 

 species of which the females are found so widely distributed. Agenor- 

 also occurs throughout the same region and is the only species of 

 which the males exhibit such a wide distribution. In regions such as 

 British Columbia, Alberta, Manitoba, Montana, and North Dakota 

 agenor is the only male Dasymutilla found in collections which could 

 possibly be the male sex of vesta. On the basis of the data of 

 geographical distribution I have therefore considered them as the two 

 sexes of the same species. The male may be easily recognized by the 

 punctate tegulae, the absence of a median pit on the second abdominal 

 sternite and by the form of the mesonotum ; the posterior third of the 

 latter is extended laterally each side into a distinct lobe. 



Although I (1923) previously stated that zella Rohwer was dis- 

 tinct from vesta Cresson, I have been forced to conclude that only 

 one species is involved after an examination of over one thousand 

 specimens from the localities listed above, and a critical study of the 

 types. Numerous variations in color of pubescence and puncturation 

 are to be found in the material studied but in practically every case 

 where variations are present, typical specimens are at hand from the 

 same localities. Certain female specimens from Manitoba, North 

 Dakota, Montana, Alberta, and British Columbia have the pubescence 

 on the head and the dorsum of the thorax blackish rather than fer- 

 ruginous; some female specimens from Kansas, Nebraska, Colorado,, 

 Oklahoma, and Texas have the broad band at the apex of the second 

 abdominal tergite silvery, narrowly interrupted medially with black, 

 and the apical fringe of the first tergite silvery, narrowly interrupted 

 medially with black. In typical specimens the apical margins of 

 both the first and second tergites are almost entirely black, the lateral 

 extremes only, with silvery pubescence. Many specimens from Ne- 

 braska, Colorado. Kansas, Oklahoma, and Texas have the legs reddish, 

 while in typical specimens the legs are almost black. Bradley (1916) 

 has pointed out that the form of the carina on the first abdominal 

 sternite of the female is not at all constant. The form of this carina 

 seems to be subject to individual variation and has little taxonomic 

 significance other than the fact that it is always more or less bidentate. 

 None of these variations are constant within any particular geo- 

 graphical region. Bradley (1916) has also mentioned that eastern 

 specimens seem to be less pubescent than western ones. This may be 

 true to a certain extent, but some eastern specimens in the material 

 studied are quite as pubescent as any of the western ones. None of 

 the variations mentioned above seem to me to be of sufficient signifi- 

 cance or stabilitv to warrant their designation with varietal names. 



