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circular opening where the orange red body of the larva can be clearly seen 

 (plate VIII fig. e). In some cases it was observed that the larva puts its anal 

 segment in the opening. 



A scheme of the development of the galls and sketches of longitudinal 

 and cross cuts of galls are given on plate XI. 



Summarizing the development runs as follows. 

 1. The egg or the larva is laid on the surface of the epidermis of the 



underside of young white, yet growing leaves near the top of the plant; 



2. around the larva the leaf develops an oval shaped swollen adge; 



3. this edge overgrows the larva and closes above it leaving only one 

 round hole, which allows communication with the air, until pupation, 

 when it is closed by the larva; 



4. under the larva the leaf tissue developes abnormally too, but not quite 

 in the same degree, as the walls enclosing it. 



The description of the larva and pupa follows here. 



The larva. 



The fullgrown larva is about 5 m.M. long and 1.3 m.M. broad. She is red 

 coloured (as the inside of a carrot). The contents of the body shines cloudy 

 through the transparent skin. On the pleural side of every segment a very 

 small black protruding spot can be seen, which is placed on a tubercle. As 

 the tracheae terminate in these black spots they surely are stigmata, so the larva 

 is amphipneustic. The larva is — as a true dipterlarva — not provided with 

 legs. The skin is absolutely bare, shiny and smooth. The anal segment 

 however shows two processes or sacks, which are of the same character 

 and colour as the rest of the segment but the ends are transparant white, at 

 least in the living larva. 



The first segment, the head, is very small and not chitinous, the 

 mandibles (mouthhooks) however are clearly visible. 



The smaller larvae show the same type and colour. 



Before pupation the larva closes the breathing hole by spinning a thin 

 membrane. A second similar membrane was found just above the pupa. 



The pupa. 



A well developed pupa is 4^4 m.M. long and n/2 m.M. broad. It has 

 in general the same colour as the larva. The sheaths of the wings and legs 

 are more transparant and of a lighter shade than the abdomen. The legs 

 are very long and reach till the half of the last segment. On the head 2 small 



