— 284 — 
of seta-pits; the posterior pair of coxe is very distinctly more 
widely separated than either the anterior or intermediate pairs, 
whilst there are eleven pairs of stigmata present, which are large 
and well-developed. Other salient characters are seen in the 
distinctive type of antenna, which do not appear to possess any 
type of sense-cone or area known in other forms, and in the 
elongate form of the ninth abdominal segment, which is distinctly 
longer than any of the preceding. 
It will thus be seen that Urothrips is sharply differentiated by 
the possession of certain characters, which from their constancy 
throughout the previously known forms might well have been 
regarded as of ordinal value; and yet in its general form this genus 
falls into the sub-order Zubulifera, despite the fact that it differs 
from true Zubulifera almost more strongly in its structure as above 
outlined than do members of the other sub-order Terebrantia. 
Regarding Urothrips as Tubuliferous, we find another series of 
characters which appear to be of more than generic value, but 
which we do not yet fully understand and appreciate. Firstly there 
is the presence of at least two minute dorsal papillae on each of the 
abdominal segments three to eight, between the lateral spine-like 
process and the stigma on each side; unfortunately these are very 
difficult to discern in our two preparations, and no such organs have 
been described in other Zhysanoptera. Secondly we notice the 
absence of the bristles seen in most Thysanoptera on the antenne, 
head, thorax, legs and abdomen, which reminds us of the vestigial 
state of the seta in two Tubuliferous genera, Zispothrips REU- 
TER (1), and Dermothrips BAGNALL (2), a condition closely 
approaching that of Urothrips. Then, from our preparations, it 
would appear that Urothrips differs in its sexual characters; we 
have searched for the characteristic organs of the Tubulifera with- 
out success, but from the nature of the preparations we have been 
unable to describe the genitalia. 
That the two specimens represent the male and female is shown 
by certain secondary characters, which we may without doubt 
(1) REUTER, « Acta Soc. pro Fauna et Flora Fennica ». 1899, XVII, n° 2, 
69 pp. | 
(2) BAGNALL, Thysanoptera in « Fauna Hawaiiensis », 1910, III, pt. VI, 
pp. 669 701, pl. XVII-XIX. 
