130 
R. S. BAGNALIi 
fig. 11); and in the male the hair is shorter and whip-like in structure, 
being uniformly thick for about one-third (0*33) its length, that is for 
about the length of the tube, and then abruptly reduced and continued 
as a long, colorless filament for not quite twice the length of the basal 
part (PL III. fig. 12). 
Habitat. German East Africa : Arusha, collected in October and 
November 1905 by Mr. C. Katona. 
Pigmentation. 
Perhaps because of the extremely dull coloring of most species of 
the Thysanoptera, the type and brightness of the coloration in Urothrips 
is at once striking. The colorless intermediate segments of the antennæ, 
too, are peculiar, whilst the strongly defined line of demarcation between 
the yellow pigmentation of the hind-part of the body and the brown 
of the fore-part, at the juncture of the meso- and metathorax, is also 
worthy of note. 
The brown and yellow pigmentation is in the cuticle itself, but 
the brilliant and very striking crimson coloration is from pigment 
deposited in the hypodermis. It will be noticed (PL III. fig. 1) that 
this hypodermal pigmentation, which is of a very coarse, granular 
nature under high magnification, is thickest in the line of the trachea, 
being more generously deposited in the region of each stigma, and 
that it is not present in any of the limbs, though found in the head 
and thorax, as well as in the abdomen. I believe that in all probability 
the hypodermal pigmentation in Urothrips has some function to per¬ 
orai, that, in fact, it is an organ of more or less importance, 
f 
Cliætotaxy. 
All the known species of Thysanoptera have a number of more 
or less conspicuous hairs or bristles present, each of which, w 7 e may 
take it, penetrates the chitin, and, being connected with a special nerve, 
constitutes a peculiarly simple sense-organ. In certain orders of insects 
the arrangement and character of these setæ is evidently of considerable 
taxonomical importance, and we may regard the Thysanoptera as one 
of these orders. 
In the Thysanoptera these hairs and bristles are found chiefly on 
the antennæ (apart from the sense-cones or sensoria), the head, the 
prothorax and legs, and the abdomen ; and those on the prothorax 
and the hind segments of the body are apparently of the first im- 
