INSKCUTOR INSCITI^ MENSTRUUS 27 



Measurements of allotype : Length 0.83 mm. ; head, length 

 0.114 mm., width 0.137 mm. ; prothorax, length 0.100 mm., 

 width 0.161 mm. ; pterothorax, width 0.211 mm. ; abdomen, 

 width 0.168 mm. Antennal segments: 1, 27^i; 2, 35[x; 3, 52^; 

 4, 48n; 5, 37n; 6, 66\i; 7, 17[x; total length of antenna, 0.282 

 mm. ; width at segment 4, 0.017 mm. 



Described from 25 females and 22 males, taken by the 

 writer on Plummer's Island, Maryland, September 14, 1913, 

 and August 16, 1914, in flowers of Impatiens sp. ; and from 

 one female taken by Dr. H. E. Ewing, at Areola, Illinois, De- 

 cember 30, 1907, hibernating in moss. 



Readily known by its sexually dimorphic coloration. 



Thrips aureus, new species. 



Female (forma brachyptera). — Length about 1 mm. Gen- 

 eral color yellow ocher,i with head and middle of abdomen 

 slightly paler, and prothorax, sides of pterothorax, and tip of 

 abdomen darker; segment 1 of antenna cream color; 2-7 

 nearly uniform light mouse gray, 3-5 usually slightly paler, 

 especially at extreme base ; ocellar pigment carmine. 



Head about 1.6 times as wide as median dorsal length, 

 two-thirds as long as prothorax, broadest slightly in front 

 of base ; cheeks gently arcuate to eyes and base of head ; frontal 

 costa shallowly notched at about 120° ; cephalic bristles small 

 and inconspicuous. Eyes about half as long as head, not pro- 

 truding, pilose. Ocelli small, about opposite middle of eyes. 

 Antennae three times as long as dorsum of head. Maxillary 

 palpi three-segmented. 



Prothorax about 1.36 times as wide as long, without evident 

 sculpture, sides somewhat flattened ; two pairs of brown bristles 

 at posterior angles; three additional pairs of smaller bristles, 

 at anterior angles, at posterior third of lateral margins, and 

 on posterior margin, respectively. Wings short, grayish, about 

 attaining first abdominal segment, distinctly rounded at apex ; 

 fore pair set with about 12 long, stout, brown bristles, dis- 



1 Ridgway. Color Standards and Color Nomenclature. Washington, 

 1912. 



