INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



27f) 



Food Plants. — The native food plants are the wild dock and canaigre 



ijiumex spp.), but rhubarb is often severely attacked. Grape vines also 

 become occasionally infested. Rhubarb is the only plant on which treat- 

 ment is worth considering. 



Control.— The adults are easily shaken upon sticky shields or into 

 oily receptacles. Neutral lead arsenate sprays should be applied when 

 the eggs begin hatching, to kill 

 the first larvae. Paris green 

 and lime may also be dusted on 

 at this time, but no poison 

 spray should be applied to 

 vegetable crops just ready for 

 market, as it would not pay at 

 that time anyway, aside from 

 the danger of the poison to 

 consumers. 



Natural Enemies. — Two 

 parasites have been reported as 

 attacking this beetle in the 

 Eastern States : Bracon gas- 

 troidew Ashm. 188 and Perilitus 

 gastrophysce Ashm. 189 



THE GRAY LEAF-BEETLE' 10 

 Qlyptosceli8 longior Leconte 



(Fig. 266) 



Fig. 265. — The green deck beetle, Gas- 

 troidea cyanea Melsh. Adults and mass of 

 eggs on a dock leaf, portions of which have 

 been removed by the beetles. Natural size. 

 I i (riginal ) 



Description.— The beetles 



are covered with fine white 



scales, giving them a grayish 



color. When these scales are removed the dorsum appears metallic 



bronze. The ventral surface and eyes are dark-brown ; the legs and 



antenna' are light brown. The length 

 varies from ^ inch to fV inch. 



Life History. — The life history of 

 this beetle has not been worked out 

 in California. The adults hibernate 

 and emerge early in the spring and 

 often do considerable damage to the 

 young foliage of fruit trees in the 

 mountainous districts. 



Nature of Work.— The adults eai 

 holes in the leaves and devour much 

 of the foliage of the trees. 

 Distribution. — This species occurs in the central and northern pails 



of the State and appears to be most abundant in the Sierra foothill 



districts. 



Fig. 266. — The gray leaf-beetle, Glyp- 

 toscelis longior Leconte. Adults, en- 

 larged three times. (Original) 



188 Insect Life, II, p. 348, 1890. 



186 Insect Life, III, p. 57, 1891. . , . . 



I90 A small green and bronze beetle, Colaspidea varicolor (v., is common throughout 

 the State and sometimes attacks fruil tiers. Pear and < 'eanol ft its are known host 

 Plants. (Fig. 267) 



