INSECT ENEMIES OF EASTERN FORESTS 565 
molt the eel is So enlarged in front that the head is concealed, and 
the body tapers toward ‘the anal end. The larva secretes a shmy 
matter which covers the body, giving it an olive-green color and 
causing it to resemble a slug. This species is an introduction from 
Europe and is distributed in ‘North America from Ontario to British 
Columbia in Canada and from the North Atlantic States to California 
in the United States. It has been well known as a pest of cherry and 
pear in the United States since late in the eighteenth century, and 
occasionally it is found 
feeding on hawthorn, 
plum, quince, and shad- 
bush. Often 20 or more 
larvae are found on a sin- 
gle leaf. Most of the feed- 
ing is done from the upper 
surface of the leaf and 
only the parenchyma is 
eaten. This gives the foli- 
age a scorched appearance 
and causes it to dr op pre- 
maturely. 
Throughout most of its 
range in the United States, 
the pear slug probably has 
two generations annually. 
Reari ing records in New 
England, however, show 
that occasionally there is  Ficure 156.—The pear slug (Caliroa cerasi) : 
a eae eT Ce ortauead Di ieat/eaten by larva, untaral 
€ enlarged 5 , re aten Dy larva, n & 
eration, and Harris (2/0) Sean eae : 
found that some individ- 
ulas remained unchanged in the ground, in a dormant condition, 
through two winters. 
The winter is passed as prepupal larvae in earthen cells or cocoons, 
composed of grains of earth and a substance secreted by the larvae. 
The adults of the first generation emerge late in May or in June, and 
those of the second generation late in July or in August. The eggs 
are deposited singly in small semicircular incisions cut in the leaf 
tissue. Hatching “takes place in about 2 weeks, and the larvae com- 
plete their orowth i in about 4 weeks. The full-grown larvae drop to 
the ground and form their cells in the soil, those of the first generation 
transforming to adults in 2 or3 weeks. Thus larvae of the first genera- 
tion may be ‘found in the field from June to early in August and those 
of the second in August and September. 
In recent years, Caliroa lineata McG. .5 & species closely related to 
the pear slug, has been causing serious damage to pin oak in New 
Jersey. 
The larva of the rose sawfly (Caliroa aethiops (F.)), also called 
the European rose slug, is yellowish green, but the food in the al- 
mentary tract causes it to appear dark olive green. The head is 
yellowish and has a black spot on each side, enclosing the eye. The 
length of full-grown larva is about 14 inch. 
