10 INSECUTOR INSCITI^ MENSTRUUS 



mozing strise, almost as in H. sericatus; posterior margins of 

 abdominal tergites 1-5 fringed at sides with numerous slender 

 spines which are not at all coalesced at base to form plates 

 or scales ; tergites 6-8 and sternites 2-6 with their entire pos- 

 terior margins similarly produced. 



Measurements of holotype: Length 1.020 mm.; head, length 

 0.113 mm., width 0.160 mm.; prothorax, length 0.132 mm., 

 width 0.228 mm. ; pterothorax, width 0.254 mm. ; fore wing, 

 length 0.792 mm., width at base 0.084 mm., at middle 0.046 

 mm. ; abdomen, width 0.276 mm. 

 Antennal segments .... 1 2 3 4 5 



Length (^x) 22 38 72 43 33 



Width (n) 29 25 20 21 17 



Total length of antenna, 0.298 mm. 



Male (macropterous). — Length about 0.85 mm. Color and 

 structure essentially as in female. Tergite of abdominal seg- 

 ment 9 with a pair of heavy, finger-like chitinous processes 

 between the usual two pairs of long bristles behind middle 

 (PI. I, fig. 5). 



Measurements of allotype: Length 0.852 mm.; head, length 

 0.098 mm., width 0.146 mm. ; prothorax, length 0.121 mm., 

 width 0.192 mm. ; pterothorax, width 0.223 mm. ; fore wing, 

 length 0.660 mm., width at base 0.072 mm., at middle 0.040 

 mm. ; abdomen, width 0.168 mm. 



Antennal segments 123456789 



Length (n) 20 33 66 41 32 35 20 19 17 



Width ([x) 26 23 18 19 16 16 12 11 6 



Total length of antenna, 0.283 mm. 



Described from 5 females and 15 males taken by the writer 

 at Plum Point, Maryland, June 21, 1914. The males of 

 this species were swarming in numbers about a few females 

 on the flowers of a wild rose in a low marshy area. 



The female may easily be distinguished by having the abdo- 

 men closely pubescent, the thorax finely striate, and the middle 

 and hind legs mostly blackish brown; while the male may be 

 known by the armature of the ninth abdominal tergite. 



