NEMATUS SALICIS-OINERB2E. 199 



Nematus Vollenhoveni, Cam., Sc. Nat., ii, 296 ; Andre, Species, 



i, 153 ; Cat., 17*, 77. 



Black, shining ; mouth, tegulae, edge of pronotum, sometimes the 

 belly and anal segment above, and legs, pale testaceous to pale or bright 

 yellow ; the tibia3 paler than the femora ; apex of hinder tibiae and tarsi 

 fuscous. Antennae a little longer than abdomen, filiform ; the third 

 joint a little longer than fourth, apical joints reddish, especially beneath. 

 Wings hyaline ; stigma fuscous, pale at the base. 



The ^ has the antennae longer and thicker, especially at the base, 

 and the stigma fuscous. 



Length 2^ 3 lines. 



A larger insect than N. c/allicola ; the antennae are 

 shorter, and sutures on vertex and pentagonal area 

 much more distinct ; posterior tarsi longer compared 

 to tibiae, with its second joint shorter compared to 

 fifth, and the stigma has only the extreme base pale. 



This species forms galls on Salix purpurea and on 

 other smooth-leaved willows. The galls are more or 

 less roundish, pea-shaped, but not unfrequently speci- 

 mens are found of an elongated form. The skin is 

 smooth and shining ; the ground colour is green or 

 yellowish-green, with or without pinkish cheeks. Not 

 unfrequently they have yellowish tubercle-like bodies 

 (apparently fungi) distributed over the surface, and 

 there may be as many as six on a single gall; the 

 internal cavity is considerable, the walls being conse- 

 quently thin. They are situated on the lower side of 

 the leaf (sometimes, however, projecting a little from 

 the upper) and are always attached to the midrib. 



The eggs are deposited in May just as the leaves 

 are beginning to burst forth ; and the galls increase 

 in size, as a rule, along with them. The larva 

 when young is rather slender ; its body glassy white, 

 except when the contents of the food canal give it a 

 greenish tinge. The head is light fuscous or brown, 

 and is covered with a few hairs ; eye-spots deep black ; 

 mandibles brown, darker at apices. When full-fed the 

 head is rather small, narrower than the second seg- 

 ment, flattish in front, and is of a grey colour with a 

 tinge of green. Bye- spots black, and a dark irregular 

 spot is placed between the eyes near the top. Mandibles 



