362 
gradually increase in length toward apex of wing. Sides of abdomen 
reticulate, sparsely spinose; posterior margins of abdominal segments 
2—8 prolonged into small equidistant flattened spines (excepting under 
the wings), which may be united at their bases into plates; tip of abdo- 
men (in female) conical, tenth segment weakly chitinized in its apical 
median half; ovipositor well developed, curved downwards. 
This genus, although seemingly a specialized one and suggest- 
ing Sericothrips Haliday, has retained certain primitive characters 
(the nine-segmented antennz, the character of the sensoria, and the 
tarsal appendage) which indicate affinities with the A%olothripide. 
In view of the fact that in all the species of the order, a change in the 
number of antennal segments always consists in a reduction and 
never in an increase in the number of these segments, it might be 
assumed that the Thripidze early divided into two branches, one of 
which, continuing more nearly along the original line, gave rise to the 
present genus, while the other produced the ordinary type of Thrip- 
idee. Heterothrips is, indeed, so sharply separated from all other 
members of its family, that a new sub-family might easily be erected 
for it; but 1t seems best to defer this until the Thripide are better 
known. 
Heterothrips ariseme@ sp. nov. (Fig. 1.) 
Female.—Length about 1.25 mm. Color nearly uniform dark 
blackish brown; tarsi, anterior tibize, and third, antennal segment pale 
yellowish. 
Head rather coarsely transversely striate, faintly but sharply con- 
stricted at posterior margin of eyes; frons acutely emarginate. Antennal 
segments 1 and 2 slightly lighter than body, shaded laterally with black, 
the former provided with a sub-transverse carina; segment 3 pale yellow- 
ish, with a narrow sub-basal white band, and apical third clouded with 
brown; segments 4—9 uniform light blackish brown, excepting the yellow- 
ish sub-apical band of sensoria on segment 4. 
Prothorax about twice as long as head and two-thirds as long as 
wide; sides and angles rounded; surface sparsely spinose, and faintly 
reticulate. Pterothorax about 1.3 times as wide as prothorax, and 
about as long as wide; mesoscutum transversely striate, and with four 
pairs of short spines; metascutum concentrically striate. Wings just 
attaining tip of abdomen; basal third widened, the sub-basal width 
slightly more than twice the sub-apical, and contained in the total length 
about 7.6 times; color blackish brown, excepting a broad sub-basal 
white band. Legs reticulate; femora nearly concolorous with body, the 
anterior pair shading to yellow at apex; fore tibiz yellow, shaded later- 
