OF WASHINGTON. 71 
ture. The mesoscutum may have a median longitudinal carina, 
as with Euplectrus, but is usually entire. The mesoscutum is 
divided from the mesoscutellum by a deep transverse suture run- 
ning between the fore wings, and which may be straight (Spa- 
langid) or concave anteriorly ( Torymus} , or posteriorly ( Cher- 
chysius}. The mesoscutellum is never entire, but consists either 
of three or of five pieces. Two very deep sutures, which usually 
converge anteriorly, separate the scutellum proper from the pa- 
raptera (MacLeay) or axillcz (Thomson), and these again with 
many genera are separated from small triangular pieces, which 
Thomson has called the axillulce. The mesoscutellum proper 
may be either unmarked or it may have a delicate transverse cen- 
tral suture (Syntomaspis} or two sublateral longitudinal parallel 
sutures (Tetrastich us}. The mcsopostscutellum is small, trian- 
gular or quadrate. The mesosternum varies considerably in 
size and shape, from a small, rounded disc to a large, irregular, 
obliquely -placed sclerite. The mesepisterna and epimera are 
large, well developed, and distinctly separated. The episterna 
project up so as to intervene between the pronotum a"nd the 
tegulce on either side. 
The metathorax. The metaprcescutum and scutum are repre- 
sented by chitinous transverse bands. The former is usually 
interrupted by the mesoscutellum and appears as a triangular 
piece on each side. The metascutum is also occasionally so 
interrupted, and appears as two patches parallel with and simi- 
lar to the above ; but it is also frequently continuous from side 
to side. The metascutellum usually contains entirely within its 
borders the metathoracic spiracles and is quite variable in form. 
It has not been used in classification to any extent except by 
Thomson. It has often a well-marked central longitudinal carina, 
which divides at the neck. The neck is the somewhat elevated 
posterior portion of his sclerite and overlaps the petiole of the ab- 
domen. There are often two lateral, usually curving, carinae, 
sometimes replaced by delicate sutures, which cut off the side 
pieces containing the spiracles from the centre of the sclerite. 
The lateral edges of the metascutellum are frequently thickened 
and often turned up, in which case they are usually furnished 
with rather long whitish hairs, as in certain of the Pteromalince . 
The metasternum is well marked, sometimes notched caudally, 
