THE SUGAR-BEET THRIPS. 7 
Prothorax transverse, about three-fourths as wide as long; length 0.158 mm.; 
width 0.232 mm.; margins rounded; a row of setae extending around the margins, 
with the exception of the anterior margin. Mesothoracic angles prominent and 
acute; width 0.282 mm. Wing pads extend to the middle of the fifth abdominal 
segment, each forewing pad bearing 12 to 13 short spines; length of wing pad from 
base to apex 0.564 mm. 
Abdomen fusiform, tapering slightly anteriorly; segments 9 and 10 much narrower 
than the rest, each bearing a pair of large obtuse spines, which extend upward. Each 
segment except 1, 9, and 10 bears two dorsal pairs of setae, one placed laterally and 
/ 
Fig. 5.— Third-stage nymph 
of sugar-beet thrips. En- 
larged about 40 diameters. 
(Original.) 
$ 
1ft- W 
m 
Fig. 6. — Fourth-stage nymph 
of sugar-beet thrips. En- 
larged about 40 diameters. 
(Original.) 
one sublaterally. The first segment is without setae, and 9 bears two pairs on lateral 
margin; 10 bears only one pair. 
Legs translucent white, bearing numerous short spines, with one long spine on 
the tibiae. 
THE ADULT. 
The adult female (fig. 7) is described by Hinds as follows: 
Heliothrips femoralis Reuter. 
Female. — Length 1.3 mm. (1.12 to 1.5 mm.); width of mesothorax about one-fourth 
the body length. General color dark brown to yellowish brown, lighter at extremi- 
ties. Entire surface of body weakly but plainly reticulated. 
Head two-thirds as long as broad, widest in front; anterior margin depressed at 
insertion of antennae; vertex carinated; bases of antennae separated by a prominence 
as high and nearly as wide as the first antennal segment ; two transverse wrinkles near 
back of head more prominent than the others; behind the anterior one of these two 
the longitudinal parts of the reticulations become very faint; spines upon head scat- 
tering and small. Eyes quite large, protruding anteriorly, coarsely granulated; 
eyes and margins of ocelli bright, dark red by reflected light; ocelli placed on sides 
