386 
Eev. T. A. MarshalFs Monograph of 
probably resolve itself into one or more of those above 
described^ some of whicb are themselves uncertain. 
Alysia brevicornis, Nees (Mon., i.^ 249) belongs to 
Aspilota, but cannot now be identified ; the characters 
assigned to it are merely generic. 
XXV. DACNUSIDES. 
Setting aside a few aberrant genera, these insects 
differ very little from the Alysiides^ of which they are 
the inferior forms, possessing only two cubital areolets. 
This character, however, is obvious and admits of precise 
definition. In many of the preceding tribe the cubital 
areolets appear confounded, but this is through the 
absence of colouring matter in the dividing nervures, 
which may always be traced, at least ideally. In 
Dacnusa and its affinities this is not the case : the radial 
nervure shows only two abscissas, i.e., after passing the 
first abscissa, it is directed in an unbroken curve to the 
tip of the wing, forming no second angle. The radial 
areolet is lanceolate, seldom cultriform (Liposcia), and 
mostly too short to reach the tip of the wing ; stigma 
variable, oval more or less lanceolate, linear and at- 
tenuated in different degrees, or lastly obsolete, being 
confounded with the metacarp {Gyrocampa) ; 1st cubital 
areolet separated from the 1st discoidal, except in 
Dacnusa aphanta; cubital and anal nervures more or 
less effaced towards the extremity. Abdomen usually 
subsessile, rarely as broad at the base as the metathorax 
(Polemon); often compressed in the ? {Chsenon, 
CoeliniuSj Polemon) y 1st segment rugulose or striolate, 
the rest generally smooth, but sometimes with a 
little rugosit}'' on the 2nd segment ; rarely with more 
of the segments rugulose [CEnonej Polemon), Terebra 
very short or concealed; rarely as long as half the 
abdomen. 
There are no apterous females, if the Chsenon apteruSf 
Curtis, be rightly considered as a synonym of Chasmodon 
{Alysiides, Gen. i., ante). At the same time it must be 
observed that, in default of wings, Ghasmodon might 
with equal propriety be referred to the present tribe. 
The Dacnusides have naturally the same habits as the 
Alysiides, being parasites of Diptera ; observations have 
shown that even the minute flies whose larvse live in the 
