l68 THE OAK GALLS AND GALL INSECTS 



time included in the same genus. This similarity is much 

 greater between tlie sexual species of the genus Dvyophanta 

 themselves which cannot in some cases be separated at all, as 

 for instance, D. tachenbcvgi and D. similis which are practically 

 identical. 



(25). Agamic Generation. I. Biorhiza aptera (Fab). 

 Gall. 



Situated on the roots of the oak, either singly or in masses. 

 According to Adler they may also appear on the leaf stalk, but 

 those that he procured in this situation soon dried up. I have 

 myself never found the gall anywhere but on the root. Colour : 

 Pink to white when young, in some cases with a purplish tinge, 

 becoming brown with age. Soft at first, hard and woody 

 later. 



Imago. 



Colour : Yellow to reddish brown. Antennae : Darker towards apex. 

 Thorax : Parapsidal furrows distinct and usually complete, mesonotum especially 

 in the centre, slightly shining. Meso pleurae pilose. Scutellum and propluerae 

 tinely punctured. Abdomen : Darker towards the apex. Legs : Yellowish 

 brown. JVings : None. 



(25). Sexual Generation. Ia. Biorhiza terminalis (Fab). 

 Inquilines. Synevgus facialis (Htg.) and S. nielanopiis (Htg). 



Gall. 



Grows chiefly on the terminal buds, but is frequently met 

 with on the lateral ones. Large, circular, and many celled, soft 

 and spongy at first, becoming hard and woody later. Colony : 

 Pink or bright red when young, turning brown with age. 

 Imago, 



Colon? : Yellow to yellowish red. Antennae : Darker towards the apex. 

 Thorax : Mesonotum shining and finely punctured. Pleurae shining andimpunc- 

 tate. Parapsidal furrows distinct. Scutellum wrinkled, with two basal foveae. 

 Abdomen : Brownish, on the dorsal surface darker in colour. Tegs : Yellowish 

 red. fVinors : Hyaline. Nervures brownish. 



Account of Generation Cycle. 



From the Biorhiza aptera galls the flies emerge in November, 

 December, and January (occasionally in March). They creep 

 up the trunk and lay their eggs very often high up in the tree. 

 The bud is first punctured with the ovipositor until riddled with 

 canals, into which the eggs are afterwards pushed, lying in a 

 mass at tb.e base of the bud. The resulting Biorhiza terminalis 



