43 



Fig 35. 



the leaves or stems, preparatory to the insertion of the eggs. Figure 15 represents 

 Earpiphorus maculatus, Nort., the Strawberry Saw-fly, in all its stages. 



The species found upon the various 

 willows- may be divided into two groups ; 

 those whose larvae feed openly upon the 

 foliage in its natural state, and those of 

 which the larva? subsist in concealment 

 upon the substance of galls, produced by 

 themselves, or by other insects, upon the 

 leaves and twigs. Of the former group 

 four species may be mentioned : 



Cimbex Americana, Leach. This is 

 the largest of all Canadian (or indeed Am- 

 erican) Sawflies, and its larva is corres- 

 pondingly voracious. The range of this 

 insect extends from " ocean to ocean," 

 and there are several varieties. In the 

 typical form the male is nearly black ; 

 the head and thorax have a bluish tinge, and the abdomen a purplish one. The female is 

 black with whitish or yellowish spots on the sides of the abdomen. Both sexes have 

 yellow feet. The antennae are also yellow, and consist of seven joints, the last three 

 forming a knob. These saw-flies vary in length from three-fourths of an inch to one inch, 

 and the male especially is a very formidable looking fly, with his long, toothed jaws and 

 big clumsy legs. The egg is placed in a slit made upon the upper surface of a leaf, pro- 

 ducing a small blister thereon. The larva is of a pale yellowish colour, with a black 

 stripe running down the back, and black dots along the sides. When full grown it mea- 

 sures about an inch and a half in length, and spins a strong brown oval cocoon, which 

 remains during the winter upon the ground under leaves and debris. In the spring the 

 larva transforms to the pupa and the perfect insect appears in May or June. 



I have found the larvse chiefly upon the foliage of elms, but they also infest the lin- 

 den and willow, and have sometimes been found very injurious to the last named. The 

 following paragraph is quoted from the Eeport of the U. S. Entomologist for 1888, from 

 a paper by Mr. Lawrence Bruner on Nebraska Insects : — 



" Unless some disease or insect enemy soon appears in sufficient strength to diminish 

 the large Willow Saw-fly (Cimbex Americana) it will completely destroy our hedges of 

 white willow that grow upon the more elevated prairies. The enemy must necessarily 

 be " natural " for the farmers will not look to the matter themselves. This year again 

 the large slug-like larvse of this insect appeared in even greater numbers than on previous 

 occasions, and over much more extended areas. In some instances the wild willows also 

 suffered when growing isolated and upon rather high ground. Several farmers followed 

 my instructions and cleared away the debris along their hedges last fall, and burned it, 

 and in that way destroyed the pupae. Where these were isolated from other infested 

 hedges the remedy was quite apparent, . but where other pupse were close at hand the 

 work made no perceptible diminution in the number of larvse present. " 



It is to be hoped that Canadian farmers in such a case would take vigorous and con- 

 -certed action, and by annually raking up and burning the leaves and debris the evil 

 would be largely overcome in two or three seasons, not only for this but for many other 

 insects. 



Trichiosoma triangulum, Kirby. — This is an insect of somewhat similar appearance, 

 but of less size than the preceding, being about three-fifths of an inch long. The head 

 and thorax are black, and the latter is clothed with long whitish hairs. The thighs are 

 bluish-black, and the rest of the legs yellow. The wings have a yellowish lustre. The 

 larvae are similar in shape and habits to those of Cimbex, but somewhat smaller, and of a, 

 pale greenish colour, without the black stripe along the back. 



