52 Rev. T. A. Marshall's Monograph of 



also ; a pale patch occupies the 2nd suture and the disc of the 2nd 

 segment. Length, 1 ; exp. 2 lines. 



This species is easily recognised by its many small 

 peculiarities ; both sexes may be known at once by the 

 unusual development of the 1st intercubital nervure ; the 

 female also by the structure of the terebral valves, 

 analogous to that which is seen in the genus Monocto^ncs. 

 Haliday procured these somewhat rare parasites by keep- 

 ing the pucerons which infest Crepis virens, hawk's-beard, 

 and Cichorium intyhus, succory ; and I obtained a fine set 

 from the pucerons of Lapsana communis, nipple-wort. 



19. Aphidius pseudoi^latani, Marshall. 



A. constridus, Hal., lib. cit., do, ^ ^ {nee Nees). 

 A fseudoplatani. Marsh., lib. cit., p. 82, ^ $ . 



9 More slender than the preceding. Pale whitish yellow ; head 

 and thorax infuscated above ; mesostemum sometimes infuscated. 

 Palpi very long for the genus. Antennae slender, blackish, with the 

 4 or 5 basal joints yellow, a little shorter than the body, 16-jointed 

 (rarely 15-jointed). Mesothoracic furrows effaced ; metathorax 

 smooth, faintly carinated and areated. Wings hyaline ; squamulae 

 and radicles yellowish ; nervures pale brown, distinct ; stigma 

 yellow during life, afterwards pale brown ; cubital nervure continued 

 to the end of the 1st cubital areolet. Legs yellow ; extremities of 

 the 4 posterior femora and tibiaj infuscated on the outer side. First 

 abdominal segment linear, slender, three times as long as broad, with 

 salientitubercles, situated in the middle. Terebra further exserted 

 than that of crepidis, its valves yellow, compressed, conic, not 

 angulated beneath, curved downwards at the apex only. ^ Head 

 and thorax black ; palpi pale brown ; antenna} 18-jointed, black ; 

 squamulfe and radicles brownish ; legs dull testaceous or brownish, 

 base of coxte, femora, middle of tibiae, and tips of tarsi, infuscated ; 

 abdomen impure yellowish, clouded with a darker tint, sometimes 

 entirely infuscated after the 1st segment. Length, 1 ; exp. 2 lines. 



Bignell has bred 2 $ s and a ^ of this species, out of 

 Drepanosiphum acerimi'tn, Walk., the puceron of Acer 

 pseudoplatanus, the sycamore. The pucerons which were 

 parasitised turned white, and two of them were winged. 

 The Chalcids Isocratus ieneus, Nees, and vulgaris, Walk., 

 are hyperparasites of this Aphidius. 



