72 DIASTROPHUS RUBI. 



two large foveas, distinctly separated from one another or not. Median 

 segment with two parallel keels. Abdomen sessile, globular, not com- 

 pressed, the second segment with the $ occupying half of the total 

 length, and having the ventral spine as long as thick. Wings ciliated, 

 the radial cellule moderate or short, broad at the base, open in front ; 

 the areolet absent or present, placed near its base. Claws bifid. 



The antennae are stout ; the joints are all clearly separated, the third 

 being the longest in both sexes, and in the $ is incised ; the others 

 from the fifth being of equal length and thickness ; the apical being 

 somewhat thinner, especially in the <£. 



The species of Diastrophus are black, with the 

 abdomen sometimes brownish, and the legs yellowish. 

 The genus comes nearest to Aulax, which is readily 

 known from it by the thorax being aciculate or aluta- 

 ceous, not shining and polished. 



There are three European species, — two, rubi and 

 Mayri, forming galls on Bubus ; the other, D. aphidi- 

 vorus, being parasitic on an Aphis ; and four North 

 American species are known. 



1 (2) Scutellar foveas distinctly separated; the scutellum not furrowed 



down the centre. Rubi. 



2 (1) Scutellar foveas confluent ; scutellum furrowed down the centre. 



Aphidivorus. 



1. DIASTROPHUS RUBI. 



PL IX, fig. 2, gall ; PI. XIII, fig. 6, ? . 



Diastrophus rubi, Htg., Germs. Zeits., ii, 194 ; iv, 410 ; Marshall, 

 E. M.M., iv, 223 ; Tasch., Hym. Deut., 

 123 ; Mayr, Oyn. Gallen, 14 ; Eur. 

 Cyn., 12. 



Andrieus Hartigi, Marshall, E. M. M., iv, 101. 



For gall and larva see Reaumur, Mem., t. 3, pi. xxxvi, figs. 1 — 

 5 ; and Malpighi, Opera, ii, tab. xvii, 

 fig. 61. 



Black; legs reddish -yellow, the coxae at the base fuscous ; antennae, 



$ 13-, (j 14-jointed, fuscous-black ; the four or five basal joints more 



or less reddish ; wings hyaline, the nervures blackish or brownish ; the 



basal abscissa of radius curved slightly, $ and $ . The $ has the third 



joint of the antennas curved. 



Length 2 — 2'5 mm. 



The face and sides of the thorax are aciculate ; the 

 tegulse vary from black to red; the oral region is 



