1878. ] The Smallest Insect Kuown. 447 
The wings are linear, of sigmoid curvature, with three or more 
longitudinal lines of minute hairs on the faces, and fringed at the 
edge with comparatively long ones, which have a black medulla 
or pith in the greater part of their length, but the inrier part, next 
the body of the wing, is so transparent as to be hardly visible, 
and gives to the fringe the appearance of being separated from 
the wing, though with high magnification the hairs can be traced 
through their entire length. In mounting this specimen the 
wings of the left side were partly torn from their place and re- 
versed, so that the foreswing is that which is seen in the figure 
nearest the rear of the body, and the hind wing is that which ap- 
pears to have its socket nearest the head of the insect. Their 
proper origin is in fact at a, whilst at 4, careful examination shows 
a slight projection or shoulder on the fore wing where a corres- 
ponding part marked 4’ on the hind wing articulates with it when 
both are in proper position. 
The legs are nearly as long in proportion to the body as those 
of the common mosquito. The tarsi are five-jointed. The tibial 
spurs are large and strongly developed on the fore legs, as shown 
at c and c’ in figure, and opposite them on the first joint of the 
tarsus the fringe of hairs is very noticeable, which is sometimes 
called the “ comb” in larger insects. The tibial spurs are insig- 
nificant on the other legs. The foot-pads or pu/villt, with the claws 
are so minute as to be scarcely distinguishable even under a power 
of four hundred diameters. 
The abdomen is pediceled, and is very short and obtuse, its 
longitudinal diameter being. rather less than its transverse. It is 
So opaque that the rings can only be well seen at the edge where 
they appear as in section, and where they have a pronounced ap- 
pearance of being telescoped, the edges passing beyond each other 
as if the abdomen had been flattened in the direction of its length. 
I should have thought this an accidental condition of the present — 
Specimen, but for the fact that Prof. Packard found it the same in 
the one described by him. Five rings can be distinctly made 
out, with the probability of a sixth, and perhaps a seventh. 
Upon the under side of the abdomen a long spike-shaped ovipos- 
itor is seen, whose form and dimensions are shown in the second 
outline of the abdomen at C in the figure. 
This description of the Pteratomus, of which all the parts have 
been carefully verified, corroborates collaterally the opinion of 
