374 



A.V ECOXOMIC EXTOMOLOGY. 



On grapes there are often black-dotted slugs, the larvse of 

 Blennocanipa pygmcsa, that do some injury ; and on roses almost 

 ever}" grower has been annoyed by numer- 

 ous green slugs, the lar^^ae of Monostegia 

 roscB, which make their appearance early in 

 the season. 



Raspberries are sometimes severely in- 

 jured by Httle spiny slugs, the larvse of 

 Mojwphadnus rubi, that appear in June or 

 early July, first eating round holes in the 

 leaves, but e\'entually, when they become 

 Grape-slug, larva of numerous cnouo-h, taking" the folia8:e com- 



7iocampa pygmcza. ° 



pletel}-. Many other cultivated plants, in- 

 cluding the strawberry, are attacked bv these saw-fly lan^se : but 

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

 against them are also verv much the same. 



The largest of our American species, Cii/ibex americojia. is 

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

 dery, whitish lan'a 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 e\'en 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 owm bulk of cheap flour. Any 

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

 w'ell as hellebore, while on the slimy types even fine road-dust 

 will quickly choke them to death. Air-slaked or dr}- 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 injur}^ 



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 



