605 
OX THE MICHOSCOPIC ANATOMY OF AN INSECT 
LAnYA.—GOBETHBA PLUMIGOBNIS. 
BY E. EAY LANKESTEE. 
K>« 
A AIONG the commonest objects of interest to be met with 
during early summer in the ponds and pools near the 
metropolis^ is a perfectly transparent crystalline little creature^ 
having much the appearance of a small glass worm. It is the 
larva of a dipterous insect the Gorethra plumicornis, and 
forms a most beautiful and instructive object for examination 
with the microscope. The larva is only about two-thirds of 
an inch long, and is easily obtained by drawing a handful of 
weed from the pond which it inhabits, and placing the mass in 
a vessel of water, when the Gorethra larvm will float out and 
make themselves apparent by their curious jerking movements, 
without which indeed they might escape observation, so 
excessively transparent and glass-like are they. Many years 
ago, before microscopes were what they are now, Mr. Pritchard 
and Dr. Goring gave a rough figure and a description of this 
little creature in their “ Microscopic Illustrations,"’'’ but both 
are so exceedingly imperfect and erroneous that they will not 
be found of any value or use at the present time. Abroad these 
larvee have been a little more carefully studied, but no general 
description or illustration of their anatomy has been published. 
Dr. Franz Ley dig in 1854 communicated a very interesting 
paper on their histology to Kolliker and Siebold^s Zeitschrift, in 
which the structure of the nervous system was figured, but no 
drawings given of other parts of the animaPs organization. A 
description, therefore, and drawings of its anatomy, which is 
exceedingly instructive, cannot but be of interest and value to 
the readers of the Populae Science Eeview. 
The Gorethra larva (fig. 1) is composed of eleven segments, 
which are not very distinctly marked, but still are recognizable. 
The first segment forms the head, and has very remarkable 
appendages in the form of prehensile and masticatory organs, 
which will presently be described ; the last is furnished with 
four terminal plates (fig. 1, r), and a terminal [n) and lateral 
(t) plume of feather-like hairs. The membrane which forms 
the wall of the body is very delicate and quite transparent, 
VOL. IV. NO. XVII. 2 s 
