DIPTERA. — NYCTERIBIIDE. 587 
They are scarcely more than one-eighth of an inch in length, and have 
six moderately long slender legs. They have at first sight the appear- 
ance of Aphides, being apterous, with two long slender antenne, and 
the mouth consists of four naked setz, equalling the antennz in length, 
and porrected ; they arise in pairs, and are not enclosed in any sheath 
nor are they palpigerous. The body is clothed with numerous long 
hairs, and each of the abdominal segments is furnished at the sides with 
a pair of long flattened articulated filaments, somewhat like those of the 
larva of Sialis lutaria, which are evidently organs of respiration, and 
kept in constant agitation in their watery abode. I know no insects 
of which these animals can be considered as the larve*; whilst as 
they possess certain points of resemblance with the permanently 
apterous Coccidz and Aphidz, it is not impossible that they may have 
arrived at the imago state. I must refer for further details to the 
description and figures which I have presented to the Entomological 
Society .of London. 
* Can they be the larve of the anomalous genus Acentropus ? 
THE END. 
