130 LEAF-MINING INSECTS 



mid-April from succulent saplings in a semi-open field, the 

 mines were already some ten to fifteen or twenty centimeters 

 in length and were about evenly distributed over stems and 

 leaves, and were developed on both the upper and the under 

 surfaces of the leaves. Later they were found on mature 

 trees, in which the nodes and leaves were crowded on the 

 very much shortened shoots of the year, the mines were to 

 be found only in the leaves; and they then conformed very 

 closely to the hitherto published descriptions. 



The larvae of the first brood remain in the mines until 

 late June or early July. The galleries increase in width very 

 very slowly but in length they increase rapidly, and wind 

 about crossing and re crossing until they involve much of 

 the upper surface. The later portion of the mines is yellow- 

 ish in color and from 2 to 5 mm. wide. 



The cocoon is spun in a curled leaf, or in a crevice of curls, 

 and is characteristic of the genus. There is a sheet of white 

 silk spun over the larval retreat. This is slightly irregular 

 in outline and about one-fourth inch in diameter and par- 

 tially transparent. When the sheet is complete holes are 

 made in it by the larva which then decorates the exterior 

 with tiny bunches of iridescent white globules that are like 

 toy balloons for fairies. The holes are probably made by 

 the mouthparts, and the material which forms the globules 

 is probably secreted by the Malpighian tubules and ex- 

 truded through the anal opening. 



The pupae are yellow in appearance and are found soon 

 after the cocoons are complete. 



The adults emerge after the middle of July when the new 

 shoots and leaves of the Madrona are well developed. 



Parecopta 



The members of this small genus remain as larvae within 

 their mines until full-fed and then emerge to spin dense, 

 semi-transparent, somewhat flattened, white cocoons in a 



