ANDEICUS C0RTI0IS. 



7. ANDEICUS CORTICIS. 



PL IV, figs. 4 (corticis) and 4 a (gemmatus) ; PI. XVII, 



fig. 3. 



Cynips corticis, Htg., Germs. Zeits., ii, 190 ; Schenck, Nass. 

 Cyn.,55, 59, 121, and 135; Kaltenbach, Pfl., 

 667; Kirchner, Cat., 23; Thorns., Opusc, 

 783. 

 Aphilothrix corticis, Mayr, Eichengallen, 7, pi. i, fig. 3 ; Adler, 

 Zeits. wiss. Zool., xxxv, 173, pi. x, fig. 7 ; 

 Licht. Cyn., 30, pi. i, fig. 7. 

 Andricus corticis, Mayr, Europ. Oyn., 25. 



— gemmatus, Adler, 1. c, 174, pi. x, fig. 7 a; Licht. Oyn., 

 31, pi. i, fig. 7 a ; Mayr, Europ. Oyn., 19. 



Brownish-black, the face and orbits brownish-red, and the base of 

 the antennae red ; the rest brownish, the thorax darker coloured than 

 the abdomen, especially at the sides ; the knees pale ; thorax smooth, 

 sericeous, the second abdominal segment sparsely pilose towards the 

 base. Agamic $ . 



Length 3i — 4 mm. 



Gall. — The gall appears in April, and is found on the 

 thick roots or on the trunk where a wound has been. 

 When young it is hemispherical or oval, succulent, 

 fleshy, and covered with a reddish or pinkish-yellow 

 skin. This early top gall drops off when mature, leaving 

 the gall proper embedded in the bark below its surface. 

 They are gregarious, convex, with a large cell and 

 with thick walls. The top falls off with the escape of 

 the insects, leaving a rugged rim, showing a circle of 

 canals on the outer edge. The galls are not easily seen 

 until the insects have left ; then the hole makes them 

 readily visible. 



The inquiline is Synergus incrassatus, the parasite 

 Torymus corticis, Gir. (Griraud). 



Sexual Form. — Black, shining; legs yellowish-red ; the coxge at the 

 base, the hinder, except at the apex, and hinder tibiae brownish ; antennae 

 brownish, yellow at the base ; ventral surface of abdomen brownish- 

 red. 



The (^ has the colour of the femora much lighter in tint ; otherwise 

 as in $ . 



Length \\— 2 mm. 



Appears in July. 



