106 ANDRIOUS AESTIVALIS. 



for the flies issuing from the galls is towards the 

 middle of April. 



Mayr reared Geroptres cerri and some PteromalidaB 

 from the galls. 



Mayr found the galls in stubs near Vienna. 



20. Andrious aestivalis. 

 PL IV, fig. 5, gall. 



Andricus cestivalis, Giraud, Verh. z.-b. Ges. Wien, 1859, 35 b; 

 Mayr, Eichengallen, 55, fig. 79; Eur. 

 Cyn., 16 ; Kaltenbach, Pfl., 672. 



Black ; head and thorax opaque ; the antennse, tegulae, legs, and 

 ventral surface reddish-testaceous ; the wings hyaline, the nervures 

 reddish. The antennae stouter than usual, 14-jointed, the joints beyond 

 the third moniliform ; the third twice longer than broad, curved at the 

 base, dilated at the apex. Head and thorax rugulose, sparsely covered 

 with a pale pubescence ; opaque ; the mesopleura? opaque, finely and 

 closely coriaceous. <$. 



Length 2— 2f mm. 



The galls occur in masses on the male flowers of 

 Quercus cerris. At the base the galls are closely 

 pressed together, but not at the apex, the apex being 

 very much wider than the base. The gall proper is 

 at the bottom, and is surrounded by a wall which 

 springs from the base and goes above it, leaving a 

 large, empty, cup-shaped space in the centre. The 

 gall is hard and woody, and contains one or two cells, 

 the cells being ovate, and having a length of from 

 2*5 to 3 mm. The colour of the gall is whitish or 

 greenish-white, and much paler than the outer skin 

 and the surrounding membrane, which is brownish, 

 more or less mottled with yellow. In shape it is 

 roughly conical, with a projecting point at the apex. 

 The outer membrane becomes shrunk and twisted, and 

 frequently curls inwardly over the top. The size of 

 the mass of galls varies, some being as large as a 

 walnut. The petiole bearing the galls becomes 

 thickened and somewhat twisted. 



