374 ^^ ECONOMIC ENTOMOLOGY. 



On gTa])es there are often black-dotted slugs, the larvae of 

 Blennocampa pygincea, that do some injury ; and on roses almost 

 every grower has been annoyed by numer- 

 ■ ^ ^' ous green slugs, the larvae of Monostegia 



roses, which make their appearance early in 

 the season. 



Raspberries are sometimes severely in- 

 jured by little spiny slugs, the larvae of 

 Monophadmis rubi, that appear in June or 

 early July, first eating round holes in the 

 leaves, but eventually, when they become 

 Grape-slug, larva of y?A«- nunierous enough, taking the foliage com- 



nocampa pygmcca. ° °. ° 



pletely. Many other cultivated plants, in- 

 cluding the strawberry, are attacked by these saw-fly larvae ; bi'.t 

 their habits are very similar, and the remedies to be adopted 

 against them are also very much the same. 



The largest of our American species, Cinibcx aniericana, is 

 found on willow, sometimes in considerable number, as a pow- 

 dery, whitish larva an inch and a half in length, with a broad 

 dark stripe on its back. 



Experience has shown that all these species are very suscep- 

 tible to the influence of white hellebore, and that even a small 

 quantity is quickly fatal. Infested plants can, therefore, be 

 cleared in a few hours by a thorough drenching with a decoction 

 of white hellebore, used at the rate of one ounce in one gallon of 

 water ; or the plants may be dusted with the powder, undiluted 

 or mixed with several times its own bulk of cheap flour. Any 

 stomach poison — e.g. , the arsenites or tobacco — will answer as 

 well as hellebore, while on the slimy types even fine road-dust 

 will quickly choke them to death. Air-slaked or dry hydrate of 

 lime burns through them in less than an hour when carefully ap- 

 plied. These insects are so easily killed that it is the fault of the 

 farmer himself if he suffers injury. 



The "horn-tails" resemble the "saw-flies" in away, but the 

 character of the ovipositor is different and rather more like an 

 auger or borer than like a saw. So, too, the species are, as a 

 rule, internal feeders instead of eating openly upon the foliage. 

 The larvae are usually slender, white or nearly so, and in- 

 fest plants ranging from the stems of wheat to the trunks of 



