76 ANDRIOUS GLANDIUM. 



1. ANDEIOUS GLANDIUM. 



PI. VIII, fig. 2. 



Andricus glandium, Giraud, Verh. z.-b. Ges. Wien, 1859, 355 ; 

 Mayr, Eichengallen, .66, fig. 92; Eur. 

 Oyn., 12. 

 — rufescens, Mayr, 1. c, 13. 



Agamic Form. — Black ; the basal five or six joints of the antennae, the 

 orbits almost entirely, the oral region, the knees, the fore-tibiae and the 

 tarsi, ferruginous. Often the abdomen is more or less brownish towards 

 the apex. Wings hyaline. Bare : the head dilated behind the eyes ; 

 cheeks with a sharp keel ; the face aciculate ; the mesonotum trans- 

 versely rugulose; scutellum coarsely reticulated or transversely rugulose 

 behind. Parapsidal furrows usually complete. 



Length 3 mm. 



The quantity of ferruginous colour on the head 

 varies considerably, and some examples are almost 

 devoid of it. 



The larvae live in the acorns of Quercus cerris, in 

 irregular cells in the inside ; the cells being variable 

 as regards the number in an acorn, and as to their 

 form. The acorns are seldom distorted or bent to 

 any appreciable extent by the larvae. The cells are 

 placed all round the acorn, are white, and surrounded 

 by a thickened wall ; in length and breadth they vary, 

 some being 3 and others only 2 mm. in length. 



They are found in the autumn. The general expe- 

 rience seems to be that they take from three to four 

 years to come to maturity; while numbers of them 

 appear, even when kept outside, never to change at all. 



No parasites have been bred from the galls, and the 

 only inquiline is 8ynergus vulgaris. 



Sexual Form. — This I have not seen, nor am I aware that the gall 

 has been described. Mayr's description is — 



5 reddish -yellow, the thorax without black, and with reddish-yellow 

 metanotum ; the abdomen at the apex above blackish-brown. Parap- 

 sidal furrows complete ; the scutellum coarsely rugulose ; the wings 

 clear hyaline, shortly ciliated on the hinder edge of the middle. Length 

 2*1 mm. 



<$ reddish-yellow, the vertex between the ocelli infuscated ; the 

 abdomen behind more or less brownish. Antennae 16-jointed (the $ 



