132 M. W. R. de V. GRAHAM 



longer than the postmarginal. Legs not stout ; spur of mid tibia half or virtually half as long 

 as the first tarsal segment. 



Gastral petiole about 1-3 times as long as the propodeum, 2-7 to 3 times as long as broad, 

 reaching well beyond the tips of the hind coxae, reticulate, broadest slightly in front of the middle 

 and constricted very slightly behind the middle, with one to two inconspicuous hairs on each 

 side. Gaster lanceolate-elliptical, as long as or a little longer than the thorax, slightly narrower 

 than the latter, 2-7 to 2-9 times as long as broad ; basal tergite occupying hardly one third of 

 the total length, its hind margin virtually straight medially (as in Text-fig. 96) ; next tergite 

 (fourth abdominal) nearly 1 -5 times as long as broad, about 1 -5 times as long as the basal 

 tergite ; following tergites strongly retracted, except the last which is about as long as broad. 



o*. Not definitely associated. A male which possibly belongs to this species resembles the 

 female except in its antennae and gaster. It has the flagellum slightly shorter than in the male 

 of aculeata (Walker), the combined length of the pedicellus and flagellum being barely 1 -2 times 

 the breadth of the head (1-3 to 1-45 times in male aculeata). 



The female of intersita sp. n. is very close to that of aculeata (Walker), which differs as follows: 

 Antennal scape reaching about to the middle of the median ocellus ; combined length of 

 pedicellus and flagellum equal to or very slightly greater than the breadth of the head ; seg- 

 ments of funicle tending to be rather longer (one to four at least slightly elongate, five quadrate 

 or slightly elongate, six quadrate or very slightly transverse). Teeth of pronotal collar more 

 distinct. Propodeal carina indicated by an obtuse ridge, sometimes by a fairly sharp one 

 especially at the base. Spur of mid tibia finer, like the hind tibial spur, and shorter, its length 

 approximately one third that of the first tarsal segment, and hardly greater than the breadth 

 of the tibia. Gastral petiole shorter, 2 to 2-3 times as long as broad, only slightly longer 

 than the propodeum, and reaching only a little beyond the tips of the hind coxae. The body of 

 aculeata is typically bright green to blue. 



Holotype $. England : Surrey, Box Hill, 17. vi. 1954, bred (K. A. Spencer) from 

 Melanagromyza aeneiventris (Fin.), in Hope Dept., University Museum, Oxford. 



Paratypes. England : Surrey, Betchworth, 2 $, 2. v. 1956, bred from Melana- 

 gromyza sativae Spencer (K. A.Spencer), in Hope Dept., University Museum, Oxford ; 

 Berkshire, Wytham, 1 $, 27.vii.1960, 2 9. 15.vii.1961, on flowers of Pastinaca saliva 

 L. {Graham) ; Bucks., Hell Coppice, near Oakley, 3 $, 1 $, 17.vii.1962, on flowers of 

 Umbelliferae {Graham), in Graham coll. 



Sphegigaster nigricornis (Nees) comb. n. 

 Chrysolampus nigricornis Nees, 1834 : 133, $. 



$. Very close to that of intersita sp. n. but differs as follows : 



Antennae (Text-fig. 105) with scape longer, reaching to the middle of the median ocellus or 

 even to the vertex ; flagellum longer, combined length of pedicellus and flagellum one to i-i 

 times the breadth of the head ; funicular segments on the average slightly longer, 1 to 3 

 slightly elongate, four slightly elongate or quadrate, five and six usually quadrate, in one large 

 female all the funicular segments are slightly longer than broad. Spur of mid tibia slightly shorter. 



The female differs from that of aculeata (Walker) as follows : 



Body dark green or blue, the head and propodeum sometimes bluish or greenish black. Teeth 

 of pronotal collar weaker. Propodeum with median carina absent, or indicated at extreme base 

 only. Spur of mid tibia slightly longer. Gastral petiole longer, 2-8 to 3-3 times as long as 

 broad, reaching far beyond the tips of the hind coxae. Size slightly less (2-6 to 3-2 mm., as 

 against 3-5 to 4 mm.). 



