— 288 — 
The presence of numerous pairs of stigmata in Urothrips, in 
place of the 4 pairs found in all previously known Zubulifera and 
in most, though apparently not in all Zeredrantia, would seem to 
suggest a primitive farm rather than a more recently evolved type, 
and it appears to us that the intermediate set of stigmata have been 
comparatively recently lost, anatomical examination of members 
of the Phleothripide showing that the main tracheal trunk on 
each side of the abdomen runs out laterally in each of the segments 
one to eight as though to open into a stigma, whereas the stigmata 
are only present in the first and eighth segments. 
If this is so, then the family Urothripide would come first in a 
svstem of classification, followed by the other Tubuliferous families, 
then by the 7hr2píde and lastly the Æolothripidæ ; and it is inter- 
esting to note that where there is a diminution either in the 
number or size of the stigmata, the external parts appear to be 
correspondingly more complex and specialized. This is shown in 
an interesting manner as regards the palpi in the above table. 
In closing our memoir on Urothrips paradoxus we expressed hopes 
that, before more fully considering the questions ofthe systematic 
erouping and position of the Zhysanoptera and their possible 
ancestry, more material might be brought to light to help us to come 
to some conclusion on those important questions. Such further 
material as we had hoped for is being discovered. Shortly before 
our memoir was published, Profr. PIETRO BUFFA, Rome, briefly 
described two new genera, Amphibolothrips and Bebelothrips (1) 
from Italy, and although he does not point out the chief morpholo- 
gical features on which we have erected the family, yet we believe 
that these genera belong to the Urothripide; and we now learn 
that specimens of Urothrips or allied forms collected in Africa 
have been submitted to our colleague Dr. TRYBOM, of Stockholm, 
whom we have asked to make a special study of the genitalia. 
(1) Burra, « Boll. del Laboratorio die Zoologia della R. Scuola Superiore 
d'Agric. in Portici », janv. 1909, III, pp. 194-196, fig. 1-3. 
