REVISION OF STREPSIPTERA PIERCE. 97 



Female. — Cephalothorax light brownish with slightly concave dark 

 band at base; as long as broad, apically sinuately truncate; trun- 

 cation a little over one-fourth the width at the spiracles. Lateral 

 margin convex. Spiracles dorsal, not reaching lateral margin. 



This description is imperfect, as it is drawn from the figure (Nas- 

 sonow, 1893 a, pi. 1, figs. 2, 3, 5). 



5. STYLOPS ATERRIMA Newport (1847). 



Stylops trimmer ana (=melittse? ) Smith, 1857. 

 Stylops aterrima Saunders, 1872. — Pierce, 1908. 

 Stylops meliltse aterrima Friese, 1906. 



Host. — Andrena trimmerana Kirby; England, April, May. 



According to Saunders the description is as follows: 



Male. — Similar to Stylops melittse, but with occipital margin of 

 head deeply excised; antennae, head, thorax, legs, and abdomen 

 black. 



Smith (1857) reproduces Newport's figure of aterrima and gives 

 his own figure of trimmerana which is from a fresh specimen. Both 

 figures agree on the following points: The first joint of the antennae 

 is long; the second very short; the third produced laterally and 

 parallel to the remainder attaining a point beyond the beginning of 

 the sixth; the fourth, fifth, and sixth joints subequal, the sixth 

 longer than the fifth. 



6. STYLOPS THWAITEI Saunders, 1872. 



Stylops dalii Thwaites, 1841. 



Stylops thwaitei Saunders, 1872. — Pierce, 1908. 



Stylops thwaitesei Saunders, manuscript correction. 



Host. — Andrena afzeliella Kirby; England, France, Germany, Swit- 

 zerland, Hungary. (See Host List for references.) 



This might be considered a nomen nudum if it were not for the 

 fact that the host determines the parasite. Hence it may be expected 

 that a valid description of the species will shortly be forthcoming 

 from Europe. 



It is very unfortunate that the name was published incorrectly. 



7. STYLOPS ADVARIANS, new species. 



Host. — Andrena advarians Viereck (det. IT. L. Viereck) ; Vancou- 

 ver, British Columbia, April 5, 1902. Described from one specimen 

 received from H. L. Viereck (pi. 3, fig. 1). 



Female. — Length of cephalothorax 0.95 mm., breadth at spiracles 

 0.96 mm., breadth at base of head 0.55 mm., distance between man- 

 dibles at base 0.16 mm. Cephalothorax light yellowish brown with 



« Male. — S. meliltse simillima, sed capitis margine occipitali profunde exciso; 

 antennis, capite, thorace, (alis?) pedibus, abdomineque aterrimis. (Saunders, 1872.) 



