1927] 
New Neotropical Thysanoptera 
243 
with six bristles beyond fork and posterior vein with seven or 
eight, positions not constant; all wing bristles long, broad, flat- 
tened, and dilated, as long as width of wing at middle. Abdomen 
strongly and sharply constricted at base of segment 2, which is 
the longest in the entire abdomen; dorsal surface with the usual 
deep, prominent reticulation at sides, but with the dorsal surface 
of segments 3-7 with three or four perfectly parallel transverse lines 
at base, between the areas of reticulation; segment 10 long, 
tubular, reticulate, somewhat constricted at base, divided above 
by a longitudinal suture ; bristles at apex of segment 9 about one- 
half as long as 10. 
Measurements of holotype (9) Length 1.05 mm.; head, 
length 0. 100 mm., greatest width (across eyes) 0.172 mm., least 
width (near base) 0.152 mm.; eyes, length (approximate) 0.092 
mm., width (approximate) 0.040 mm.; prothorax, median 
length of pronotum 0.090 mm., width 0. 180 mm.; pterothorax, 
width 0.248 mm.; fore wings, length 0.780 mm., width at 
middle 0.046 mm., just beyond scale 0.076 mm.; abdomen, 
width 0. 285 mm. 
Antennal segments: 12345678 
Length ( M ) 20 34 65 42 36 25 12 30 
Width (ju) 24 30 15 17 18 17 11 5 
Total length of antenna 0.26 mm. 
Trinidad; C. B. Williams; on an unidentified plant. 
This is the only New World species with eight-segmented 
antennae. The curious transverse lineation of the abdomen is 
also distinctive. 
Tryphactothrips brevipilus sp. nov. 
Female (macropterous) . — Length about 1.04 mm. Dorsal 
surface deeply reticulate. Color yellowish brown, with middle 
of pterothorax and last three or four abdominal segments paler 
and more yellowish; segment 10 of abdomen shading to gray in 
apical fourth ; antennae yellow, with segment 2 decidedly darker 
than 1 and brownish at sides and base, 3-5 pale lemon yellow 
except apex of 5 which is washed with gray, 6 yellowish gray; 
