494 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.40. 



mandibles 0.09 mm. Cephalothorax orange yellow, with disk 

 lighter, and with a dark brown band behind the spiracles; cephalo- 

 thorax as long as broad, rather narrowly truncate at apex, truncation 

 less than one-third the breadth at the spiracles. Lateral margin 

 almost straight from spiracles to apical truncation. Mandibles 

 obtusely rounded, with a small blunt tooth at apex. Spiracles 

 visible at margin but not prominent. Cephalothorax very slightly 

 constricted behind spiracles. 



Type.— Cat. No. 13689, U.S.N.M. 



STYLOPS ASTERIDIS, new species. 



Host. — Andrena asteris Robertson (det. Robertson), Carlinville, 

 Illinois. Described from one female collected September 8 by Charles 

 Robertson. 



Female. — Length of cephalothorax, 0.76 mm., breadth at spiracles 

 0.79 mm., breadth at base of head 0.54 mm., distance between 

 mandibles 0.14 mm. Cephalothorax orange yellow, lighter on disk, 

 with brown band at base; cephalothorax almost as long as broad, 

 truncate at apex, truncation less than one-fourth the width at the 

 spiracles. Lateral margin slightly convex from spiracles to trunca- 

 tion. Mandibles obtuse, with a rather acute outwardly curved 

 tooth on the inner apical angle. Spiracles lateral, but not prominent. 

 Cephalothorax broader behind spiracles and then very strongly 

 constricted. 



Type.— Cat. No. 13690, U.S.N.M. 



STYLOPS CLAYTONLE Pierce. 



Stylops claytonise Pierce. 

 Stylops imitatrix Pierce. 

 Var. $. claytonise vierecki Pierce. 



Mr. Viereck considers that the host bees Andrena claytonise and 

 A. imitatrix are synonymous and that he considers A. texana as a 

 variety of claytonise. Following his lead the writer finds the para- 

 sites of the first sufficiently close to be considered identical, but the 

 parasite of texana is quite different, as is shown by the preceding 

 table. For this reason vierecki is now to be construed as a variety. 



STYLOPS HARTFORDENSIS Pierce. 



Mr. Viereck now considers Andrena liartfordensis a synonym of 

 A. nasoni, but the writer has concluded that the parasites are suffi- 

 ciently different to retain their specific rank. 



STYLOPS MANDIBULARIS, new species. 



Host. — Andrena mandibv.laris Robertson (det. Robertson), Carlin- 

 ville, Illinois. Described from one female collected April 10, by 

 Charles Robertson. 



