230 



A A' ECONOMIC ENTOMOLOGY. 



Diseased 

 larva of clover- 

 leaf beetle. 



quite early in the season, often threatening entire destruction of 

 the crop when they are nearly full grown. Fortunately, nature 

 has provided a check for this insect in a fungous disease which in 

 most localities carries off the larvae annuallv, iust 

 Fig. 235. before they mature, leaving only a comparatively 

 small proportion to perpetuate the species. As 

 this disease seems to occur in seasons of all kinds, 

 and irrespective of climatic conditions, it can be 

 easily introduced into any locality in which the 

 insects become destructive. Affected lar\-ae curl 

 themselves round a spear of grass or on the edge 

 of a leaf and die, first swelling somewhat and 

 becoming gray in color ; then they collapse and 

 become black, eventually forming a small, dried, 

 black mass, utterly indistinguishable in character. 

 The ' ' white-pine weevil, ' ' Pissodes strobi, is one of the most 

 serious enemies to that tree, and in the more northern States 

 attacks the leading shoots, in young trees spoiling their shape 

 completely. The insect has been studied, and a full account 



is given in the Fifth Report of 

 the United States Entomological 

 Commission, dealing with forest 

 insects, but no satisfactory reme- 

 dial measures are proposed. In 

 parks or gardens small orna- 

 mental trees can probably be 

 protected by keeping the leading 

 shoots sprayed during the spring 

 with a carbolated soap-wash, to 

 which Paris green has been 

 added at the rate of one pound in one hundred and fifty gallons 

 of water. Other infested shoots should be gathered and burnt. 

 The report above cited is so full on the subject of forest insects 

 belonging to this series that only those infesting cultivated crops 

 need be discussed here. 



Early in the season we find on the leaves and stems of rhubarb 

 a rather long, cylindrical weevil, Lixus concavus, with a short 

 heavy snout, entirely covered by an easily rubbed off, rusty 

 powder. It is also remarkable for its exceedingly firm texture. 



White-pine weevil, Pissodes strobi 

 its larva ; b, its pupa. 



