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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 15 



and to become a blotch. The mines are most conspicuous from the 

 upper surface of the leaves and may be very numerous in a leaf. 

 Counts were made of the mines in six different leaves and the num- 

 ber varied from 24 in the least to 116 in the worst infested leaf. 



The young larva is greenish-brown in color with a. 

 dark brown head. The body is somewhat flattened, 

 the prothorax is broadened and the thoracic legs 

 are present at least during the latter part of its life 

 as a miner. The abdominal segments are prominently 

 enlarged on each side, giving the appearance of a 

 Coleopterous larva. When ready to leave its mine 

 the larva is about 1% mm. in length (Fig. 12). 

 The full-grown larva is about V^ of an inch in length. 

 When the larva has completed its growth in the 

 mine it cuts its oval case out of the mine. The larva 

 then walks out on the leaf and deftly twins, the case 

 over so that the thicker piece from the lower epi 

 dermis is on top. The larva develops slowly, occu' 

 pying nearly the whole summer to complete its 

 growth. I am not yet sure of the number of instars 

 and molts but head measurements indicate five molts. 

 Fig. 12. Larva of The final case of the larva in the fall consists of 



"■St a mitrSf fo"^ °™l Pi««^. t^™ =»"a>l i"™"- °™^ ^"d twa. 

 leaf. large outer ones. 



The process of cutting out a piece of the leaf for the case is an interest- 

 ing one. The larva when feeding attaches its case to the leaf by short. 



silken cords at intervals about the 

 edges. These cords are composed 

 of many threads spun in such a 

 manner that they cross each other 

 near the middle and form an X- 

 shaped cord. When ready to cut 

 out a new piece for its case the 

 larva cuts a half -oval slit in the leaf 

 which extends about half around 

 the old case (Fig. 13). It then cuts, 

 a half oval about the opposite end 

 of the case and later joins the ends 

 of the slits, thus completing the circle. 

 The new piece, however, is held in 

 place by tiny strands of leaf tissue 



Fig. 13 The case of Paraclemensia which the caterpillar leaves for sup- 

 aceriioliella, note the circle nearly cut .^ t ^ u 4-1, i 



around the case. Ports. Later, when the larva is. 



