36 BULLETIN 66, UNITED STATES NATIONAL MUSEUM. 



Two of the above instances are on the initiative of the writer with 

 the support of Mr. Viereck, the describer. The latter stated (Viereck, 

 1904, 222) concerning his Andrena junonia — 



This may be solidula altered by Stylops. 



The species were separated thus: 



9 Face with ochreous hairs; first recurrent nervure received beyond the middle 

 of the second submarginal cell; pleura with pale pubescence — solidula. 



Face with ochreous hairs; first recurrent nervure received before the middle of the 

 second submarginal cell; pleura with pale pubescence — junonia. 



Both junonia and solidula are parasitized by Styloiis solidulsc. 

 Andrena angustitarsata was described thus: 



9 9 mm. Pubescence ochreous; fovea ochreous. This is a stylopized specimen 

 and may be an aborted A. sublilis, the abortion due to the presence of the stylops. 



The species is separated from subtilis as follows : 



9 Metatarsus of posterior legs one-half as wide as the tibiae at apex; inclosure 

 smooth; abdomen indistinctly fasciate — angustitarsata. 



Metatarsus of posterior legs more than one-half as wide as the tibiae at apex; inclosure 

 smooth; abdomen fasciate; clypeus indistinctly punctured, dull, pubescence sparse — 

 subtilis (Viereck, 1904-1906). 



Several interesting points in nomenclature have been worked out, 

 among which probably the most interesting is as follows: 



Andrena convexiuscula and Andrena afzeliella were both described 

 by Kirby on the same page, the former being placed first. Smith 

 (1855, 103) found that convexiuscula was a form entirely due to par- 

 asitism and only existed as parasitized individuals, which according 

 to Perez (1886) are usually unable to reproduce. Perez found that 

 afzeliella is the normal, unparasitized form of the same species, 

 although certain unmodified individuals were found parasitized. He 

 therefore wrote the species Andrena afzeliella convexiuscula Kirby 

 (Perez, 1886). Dalla Torre (1896), following a strict interpretation 

 of the rules of priority, wrote the species Andrena convexiuscula 

 (stylop.) afzeliella Kirby in which he incorrectly stated the case. 

 Alfken on the other hand in 1899 reversed the matter and restored 

 Perez's manner of naming it. In order to be certain on this matter 

 the writer placed the question before Dr. C. W. Stiles, who decided 

 that the first decision, that of Perez, should stand. 



In the list of hosts in the genus Andrena several forms of nomen- 

 clature will be noted: 



1. u Andrena oicolor Fabr. form gwynana K. (sestival)," indicating 

 that the two generations of this species are dissimilar and have 

 received different names. 



2. "Andrena afzeliella K./' indicating a typical species. 



3. u Andrena afzeliella K. (stylop.) convexiuscula K.," indicating a 

 form due entirely to stylopization. 



