ii4 The Scottish Naturalist. 



HP HE larva of Nematus Degeeri is one of the commonest 

 ■*■ birch feeders in Scotland ; in some localities it may be 

 found in very great numbers. Stephens, alluding to the perfect 

 insect, says in his Illustrations, that it is "apparently very rare " 

 in the south, and the imago is certainly not so common as the 

 larva. 



Larva. — Head somewhat roundish, narrower than the 

 second segment, light shining-green, with a yellowish tint, 

 covered with short white hairs ; eyes small and deep black ; N 

 mouth organs brown, mandibles black at the tip ; feet, light 

 whitish-green ; claws brown, black at the extreme tip. The 

 fourteen claspers, light green like the body; the fourth and 

 eleventh segments have none. The body when old is whitish- 

 green throughout, without any marks whatever. The segmental 

 divisions are well marked, being much whiter- than the other 

 parts; when filled the dorsal vessel is noticeable by being dark 

 green. A very few short hairs are scattered over the skin. , 

 The larvae when young have a brighter and greener tint than 

 when old. The body is flattish, broad at the thorax, getting 

 narrower towards the anus. 



The larvae are found gregariously, from August to October, on 

 upper surface of the birch leaves, the epidermis of which they 

 devour. They do not often eat it through, but only the 

 upper portion, and when they do so, the fibres remain like a 

 net-work. They are very sluggish and remain almost motion- 

 less, with the body closely pressed against the surface, and 

 lying at full stretch on the leaves. I am not sure that they 

 do not reside on the same leaf during all their larval life. 



When the creatures become full-fed, they drop to the ground. 

 In the breeding jar, the cocoons, which are oblong, about 4-5 

 lines long, were spun one against the other, on the under sur- 

 face of the leaves or singly in the earth. The cocoon is thin, 

 composed of two distinct coverings, but some larvae, for 

 some reason or other, only spin the inner one. After being 

 some time in the cocoon, the larvae become shorter and stouter, 

 and the claspers shrink in. About the beginning of May they 

 enter the pupal state. 



The pupa displays all the parts of the future insect. It is 

 bright green, with transparent white antennae, feet and wings ; 

 the eyes brown. After the insects leave that condition, they re- 



