SHADE TREE INSECTS 45 



type. The mature caterpillar which feeds externally is about 3^ inch long. 

 The head is brown, and the body yellowish-green with hairs projecting from 

 white tubercles. 



The pupa is spindle-shaped, about 1/8 inch long, brown in color and shows 

 many of the adult structures. 



Life History. The moths begin to appear about the last of June, become very 

 abundant before the middle of July, and disappear by about the end of that 

 month. Several days after appearing they begin to lay their eggs, apparently at 

 night. Sixty or more eggs ma\- be laid by one female. The eggs are laid singly 

 on either side of a leaf and on any part of the surface although there is some 

 preference for a position next to the midrib or other prominent vein. The eggs 

 hatch in about 2 weeks. The young caterpillar bores through the bottom of the 

 egg into the leaf where it constructs a small, blotch-like mine which soon becomes 

 linear and winding with slighth' enlarged ends. It tends to avoid chewing through 

 the large veins. Most of the completed mines are about M inch long. When 

 the insect is abundant, 30 or more mines may be found in a single leaf. The 

 caterpillars molt twice in the mine. The time spent in the mine varies greatly 

 but under normal conditions is about 24 to 31 days. Caterpillars were found in 

 their mines until mid-September. To emerge from the mine a caterpillar cuts a 

 crescent-shaped opening in the lower surface of the leaf, and soon afterwards 

 it constructs on the surface of the leaf a small, oval, silken web under which it 

 molts. Upon leaving this web it feeds from 1 to 9 days on the lower leaf surface, 

 skeletonizing it. It then constructs another web, molts again, emerges, and con- 

 tinues feeding, this time much more e.xtensively. The injury to the foliage be- 

 comes most noticeable at this time, usuall}^ during late August and through most 

 of .September. Severely injured leaves die and fall to the ground. The cater- 

 pillars feed for several days, then drop to the ground on silken threads and spin 

 their cocoons under various objects in the debris on the ground. Pupation soon 

 occurs and the insect passes the winter in that stage. There is one generation a 

 year. 



Control. To control this insect, spray both sides of the foliage thoroughly 

 with lead arsenate at the rate of 4 pounds to 100 gallons of water, with 2 pounds 

 of flour or 1 pound of calcium caseinate added as a sticker. This spray should be 

 applied when the caterpillars begin to feed externally on the leaves, which is 

 usually a little before or about the middle of August. 



Friend, R. B. Conn. Agr. Exp. Sta. Bui. 288:395-486. 1927. 



Elm Casebearer 



Coleophora limosipennella Dup. 



This peculiar insect, which is found in the eastern United States, was evidently 

 introduced from Europe, the first specimens having been reported in 1901 from 

 the vicinit}- of New York City. In this country only elm seems to be attacked, 

 English and Scotch elms evidently being preferred. In Europe birch and alder 

 are also attacked. 



The caterpillars work at first as leaf miners but soon become casebearers, in 

 both forms feeding on the inner tissues of the leaves. The areas mined b\- the 

 casebearers are more or less rectangular in shape, being bounded by the larger 

 veins of the leaf. The cases of these caterpillars stand out at right angles to the 

 leaf surface while the larvae are feeding. This habit of forming cases distinguishes 

 this species from the caterpillars of the elm leaf miner, Kaliosysphinga ulmi. 



