10 



doubtedly prove to be ideutical with the latter. I have not seen au- 

 thentic specimens of Norton's species, but there are no characters, 

 indicated by Mr. i^'orton in his description, sufficient to separate 

 the two species. Norton's specimens were collected in New England, 

 but if they prove to be the same as the European species it would indi- 

 cate that the species was imported very much earlier than Mr. Jack 

 supposed. The European species is widely distributed, occurring' 

 throughout southern and central Europe and also in eastern Siberia, 

 and is a well known rose pest, exactly agreeing in habit with the spe- 

 cies described by Mr. Jack. Like the larvjB of Cladius pectinicornis the 

 larva of this imported insect eats the entire substance of the leaf, but 

 differs from the former in that it eats along the edges of the leaf with 

 the body more or less beneath the leaf, and when at rest remains curled 

 up on the under side of the leaf in a spiral or ball. The larva of the 

 latter is easily distinguished also by being smooth and by having a 

 yellowish-brown head with a broad brownish-black mark above. The 

 body is dark green above, with the sides and legs grayish-white. There 

 are several yearly broods, the larviie appearing from May to October. 

 The eggs are placed singly, but scattered to the number of three to 

 seven, on the under sides of the leaves and the ftill-grown larva bur- 

 rows, as stated, in the rotten wood or the pith of plants — very fre- 

 quently of rose stems — to pupate or, in the case of the fall brood, to 

 hibernate. 



SUM3IARY OF THE HABITS OF THE THREE SAW-FLIES AFFECTING^ 

 ROSES IN THE UNITED STATES. 



The following brief summary of the habits of the three species of saw- 

 flies mentioned in the foregoing pages as affecting cultivated roses in 

 this country will serve to enable anyone to distinguish the species and 

 determine the depredator in any particular case. 



The American Eose Slug {Monostegia ro.sYc).— This is the old and 

 well known species, and the only one which, up to within the last few 

 years, has been recorded as affecting the Kose in this country. It was 

 originally found in the Eastern States, but has now become widely dis- 

 tributed by being transported from place to place in connection with 

 rose plants. It is single brooded, the flies emerging in May, or about 

 the time the Eose is in full leaf. The eggs are circular and are inserted 

 singly in the edge of the leaf, on the under surface. The larva is about 

 one-third of an inch long, and slug-like, the thorax being swollen; but 

 it is not slimy, as is the case with many other allied saw-fly larva?. It 

 feeds only at night, and always on the upper side of the leaf, skeleton- 

 izing it rather than eating the entire substance. During the day it 

 remains at rest, concealed on the under surface of the leaf. 



The larval period lasts from fourteen to fifteen days, when the larva 

 abandons the damaged plant and enters the soil, where it constructs a 

 fragile earthen cocoon. In this it remains dormant until the following 



