ON UROTHRIPS PARADOXUS. 
133 
Beticulation. 
A very conspicuous and regular network, which is, as a rule, 
heaviest upon the head and prothorax, is found in several species of 
Thysanoptera, being well exemplified in the genera Parthenothrips and 
Heliothrips, and when so strongly pronounced is useful in classification. 
This reticulated structure has not been noticed in the Aeolothripidae 
is found in a few genera of Thripidae, and is very rare in the Tabuli - 
fera. Hinds says that the has discovered it in an undescribed species 
of Phloeothrïpiâae, whilst I have noticed it in two species (referable to 
the one genus) from the Hawaiian Islands. In Urothrqjs strong reticu¬ 
lation is very conspicuous at the back of the head (PI. III. fig. 3). 
Coxæ. 
In the Aeolothripidae, Thripidae and Phloeothripidae , without 
exception, we find that the intermediate coxæ are much more widely 
separated than either the anterior or posterior pairs. This is therefore a 
very important character in the Thysanoptera, which is not, however, borne 
out in Urothrips, the hind pair of coxæ in that genus being the most 
widely separated. 
Ninth abdominal segment. 
The ninth abdominal segment of Urothrips is strongly characteristic. 
Instead of being a short segment it is longer than any of the preceding, 
being as long as the seventh and eighth segments together. As already 
stated it is without spines or prominent seta-pits, but on the under 
side of the ventral plate there appears to be an organ which I cannot 
make out, or understand, and which does not appear to have been 
previously noted in the Thysanoptera. It is found in the middle of the 
front margin, is present in both sexes, and looks like a short, broad 
carina formed by a strong thickening of the chitin (PI. III. fig. 10a). 
Eleventh abdominal segment. 
Buffa has recently shown that the Thysanoptera possess in reality 
eleven abdominal segments, the eleventh segment in the Tubulifera 
being that part of the tube from which the long hairs encircle it at 
tip. In all the species I have had the opportunity of examining, each 
alternative hair is a short one. In some species the short hair in the 
mid-line, viewed dorsally, is slightly flattened, whilst Buffa describes 
