1^6 THE OAK GALLS AND GALL INSECTS 



Andricus tvilineatus. Common. These galls are usually very 

 difficult to see until the insects have emerged. They may, 

 however, form swellings, especially when they occur on the leaf 

 stalk. 



First appearance noted, June nth. 



(14.) Agamic Generation. IV. Andricus globuli (Htg.) 



Inquilines. 5. nervosus (Htg.), S. vulgaris (Htg.), and S. ruficornis 

 <Htg.) 



Gall. 



Found in the bud in September, surrounded at the base with 

 bud scales. Falls to the ground in October. Colour : Green, 

 often having some lighter spots upon it. Shape : Globular. 

 There is an inner gall with a large larval cavity,which is covered 

 with an outer green rind. This rind falls off at maturity, 

 leaving the woody inner gall exposed. This inner gall is 

 furrowed. 



Imago. 



Colour: Black. Antennae: Brownish. Thorax: Dull, may be pubescent; 

 mesonotum slightly punctured. Abdojnen : Shining, ventral surface reddish 

 brown, darker above. ■L^g's : Reddish brown ; coxae and four posterior tibiae 

 infuscated. Stiff erect hairs on the fore tibiae. 



(14.) Sexual Generation. IVa. Andricus inflator (Htg.) 



Inquiline. Sapliolytus connatus (Htg.) 



Gall. 



Resembles a thickened shoot. Colour : Light yellowish green 

 with a red apex when young, becoming brown and woody later. 

 The inner gall enclosing the larvae is yellowish brown, smooth 

 and oval, situated near the base of the cavity of the gall. 



Imago. 



Colour: Black. Antennae : Dark, reddish yellow towards the base. Thorax 

 and Head: Black, slightly shining mesonotum shagreened. Abdo?nen: Reddish 

 beneath, dark above. The male, according to Adler, has the abdomen entirely 

 dark. Legs : Reddish brown, posterior tibiae and coxae dark. 



Account of Generation Cycle. 



The flies from the A. glohuli galls emerge at the end of March 

 or during April. When ovipositing the insect directs its 

 ovipositor under the bud scales, the eggs being placed in the bud 

 axis, one eg^ in each bud. 



