394 Rev. T. A. Marshall's Monograph of 
iv. DacnusAj Ealiday, 
Hal., Hym. Brit., ii., 5 (1839). 
Body short or moderately elongate ; general form like that of 
the Alysiids, especially of the genus Adelura. Head transverse, 
rarely as long as it is broad (Z). gilvipes) ; mandibles quadridentate ; 
maxillary palpi 6-, labial 4-jointed. Antennae generally setaceous, 
multiarticulate, as long as the body or longer, often more than 
twice as long ; short and pauciarticulate in the $ of D. ampliator. 
Mesothoracic furrows usually incomplete, or hardly inchoate ; 
between them is a medial channel more or less distinct and of 
variable length, ending in a fovea before the scutellum ; meta- 
thorax short, rugulose, often imperfectly carinate at the base. 
Stigma elongate, linear, of variable thickness, emitting the radial 
nervure before the middle ; 1st abscissa distinct, but exceptionally 
cut off by the stigma in D. aclduda ; radial areolet semi- oval, 
lanceolate, acuminate ; radial nervure forming an irregular curve, 
sinuated near the middle, and straightened towards the extremity, 
the sinuation is sometimes barely visible {D. semirugosa, etc.), the 
straightening is constantly present ; recurrent nervure in most 
cases rejected, i.e., pointing to the lower angle of the 1st cubital 
areolet ; but in D. abdita, and two or three more species it is 
interstitial, i.e., pointing to the lower interior angle of the 2nd. 
Abdomen subsessile, rarely subpetiolate, oblong-oval or suborbi- 
culate, sometimes spatulate, not or hardly longer than the head 
and thorax ; all the segments smooth except the 1st, and rarely the 
2nd {D. semirugosa, etc.) ; 1st segment longer than broad ; seg- 
ments 2-3 united by coalition, and longer than all the following 
taken together. Terebra short, almost concealed, rarely somewhat 
exserted (D. areolaris), or even as long as ^ or f of the abdomen 
{D. clandestina and stramineipes). 
This genus is numerous in species, but they have been 
so neglected by hymenopterists that any attempt to give 
an account of them must necessarily be unsatisfactory. 
The earliest notice of them was published by Nees von 
Esenbeck in the '^Berliner Magazin^' for 1814: he 
described three or four species under the generic name 
of Bassus. These he afterwards, in his Monograph (1834), 
transferred to the genus Alysia, as a 5th section, with 
additions, raising the number to 12, not all of which can 
now be recognized. The only other publication of value 
on the subject of these insects is Haliday's tract dated 
1839, under the title " Hymenoptera Britannica : Alysia, 
