124 INSECTA. 
Donacia, Fab.—Lertura, Lin., 
Where the posterior thighs are large and inflated; the antenne are 
of equal thickness throughout, and their joints are elongated ; the 
eyes are entire, and the last joint of the tarsi is enclosed for most of 
its length between the lobes of the preceding one. 
These Insects are frequently ornamented with brilliant colours, 
bronzed or gilded. Several are likewise covered with an extremely 
fine and silky down, which may prove useful to them when they hap- 
pen to fall into water, as they live on aquatic plants, such as the Iris, 
Sagittaria, Nymphoea, &c., to which they cling with great tenacity. 
Their larvee live in the roots of the same plants. Their chrysalides, 
according to the observations ‘of M. A. Brongniart, are attached to 
their filaments by one edge only, forming knots or bulbs. 
The anatomical researches of M. Leon Dufour have induced him 
to think that the Donacize should form a particular family. Their 
hepatic vessels, in number, arrangement, form, and structure, consti- 
tute a very remarkable exception to those of the Tetramera, and one 
which even appears to be peculiar to these Insects. These vessels 
only open into the chylific ventricle, while in all the other Tetramera 
dissected by this able anatomist, they have two insertions, one ven- 
tricular, and the other cecal. These biliary dticts, only four in 
number, are of two different kinds; those of the first are capillary, 
disposed in two strongly flexed curves, and are inserted by four dis- 
tinct ends into a short obround vesicle, situated at the inferior and 
somewhat lateral extremity of the chylific ventricle; the others, much 
shorter, thicker, more dilatable, thin and tapering at both ends, have 
one extremity free, and are separately inserted by the other into the 
superior and dorsal region of that organ. The whitish pulp con- 
tained in them is considered by M. Dufour as alimentary matter. 
The cesophagus is capillary, and without any dilatation in the form 
of a crop. The chylific ventricle is roughened with very salient 
papille. The testes are very similar to those of the Lepture. The 
larve are naked and concealed, as well as those of the last Longi- 
cornes, an observation which strengthens the conjectures of M. 
Dufour. 
Hammons, Meq., Dey, 
The Heemoniz are Donaciz in which the penultimate joint of the 
tarsi is very small, in the form of a knot, almost entire; the last is 
very long*. The 
Perauristes, Lat. 
United by Fabricius with the Lem, or our Crioceres properly so 
called, also have very stout posterior thighs; but the eyes are emar- 
ginated ; the antenne, as in the latter, are generally composed of 
shorter joints, and the lobes of the penultimate joint of the tarsi are 
much less elongated, and merely clasp the root of the following 
one f. : 
* The D. equiseti, zostere, Fab. 
+ The Lema varia, posticata, Fab, 
