74 MASS. EXPERIMENT STATION BULLETIN 353 



Description. The adult is a sawfly from % inch to 1 inch long. The fore part 

 of the body is shining black in color. The abdomen is steel-blue and has on each 

 side three or four oval, yellowish spots which vary in size in different individuals. 

 The wings are semitransparent, smoky-brown in color, and measure about 2 

 inches when spread. The body of the male is somewhat thinner and longer than 

 that of the female. 



The mature larva is between % inch and 1 inch long. It is pale yellow with a 

 black stripe along the middle of the back. The body bears numerous small, 

 flattened, wart -like growths. Along the side near the lower edge is a series of 

 small, black spots. When at rest the larva characteristically assumes a curled 

 position like other sawfly larvae. 



The cocoon in which the larva pupates is tough and coarse, broadly oval in 

 outline, dark brown in color, and about ^4 inch to 1 inch long. 



Life History. In the spring, about May, the adult sawflies appear. The females 

 insert the eggs singly into the tissues of the leaf. The places where the eggs are 

 laid appear as tiny, blister-like swellings and are most easily seen from the under 

 side of the leaf. From 1 to 12 eggs or more may be placed in a single leaf, and one 

 female may lay about 500 eggs. After several days the eggs hatch and the in- 

 dividual larvae finally emerge from their tiny eel! through an irregular slit in the 

 leaf. The newly hatched larvae are uniformly curled up on the under side of the 

 leaves. They feed on the foliage and become full grown in late July or in August. 

 They then go to the ground near the base of the tree on which they developed and 

 spin a tough, coarse, silken cocoon among the debris or just below the surface of 

 the ground. The insect passes the winter in the larval stage, pupates in the 

 spring, and emerges as the adult about May. There is thus one generation a 

 year. 



Control. Usually' not enough damage is done in this region to warrant the use 

 of control meabures. If treatment should be necessary, a spraj' consisting of 4 

 pounds of lead arsenate to 100 gallons of water, with the addition of 2 pounds 

 of flour or 1 pound of calcium caseinate as a sticking agent, is effective. This 

 should be applied when the larvae are 3'oung and small. In some sections of the 

 West where the insect is considered an important pest of willows, raking and burn- 

 ing the cocoons in the late fall and early spring have proved satisfactory as sup- 

 plementary control measures where only a few trees are concerned. 



Felt, E. P. N. Y. State Mus. Mem. 8(1) :155-158. 1905. 

 Severin, H. C. S. Dak. Exp. Sta. Circ. 22. 1921. 



Maple Petiole Borer 



Caiilacainpus acericaulis MacG. 



In 1909 this insect was first discovered in Connecticut. It has since been 

 found in Massachusetts. 



The tiny larvae tunnel in the petioles, or leaf stems, of sugar maple, causing 

 them to break off 14 to 3^ inch from the blade of the leaf. The blades fall from the 

 tree in late May and early June. The leaf stems fall one or two weeks later. 

 The lower parts of the tree are usually affected. In a serious infestation a tree may 

 lose as much as one-third of its foliage. 



Description. The adult is a small, four-winged fly known as a sawfl\'. The 

 wings are transparent. The fore part of the body is black; the abdomen and 

 legs, honey yellow. 



