274 



INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



inactive only on cold clays. During the early spring months (March 

 and April) egg-laying begins much as in the case of the other species 

 of Diabroiica — the eggs being deposited under the surface of the soil 

 about the base of the food plants. The larvae work upon the roots 

 underground while the adults feed upon the 

 huds, flowers, young fruits and foliage above 

 ground. There are evidently two broods a year. 



Nature of Work. — The nature of the work of 

 the striped species is practically the same as that 

 of the preceding species. 



Distribution. — This beetle is generally dis- 

 tributed throughout the entire State, being quite 

 abundant in many localities, in the northern as 

 well as the southern parts. 



Food Plants. — The following plants are at- 

 tacked by the beetle : almond, apple, apricot, 

 bean, beet, cucumber, muskmelon, pea, prune, 

 pumpkin, squash and watermelon. Many other 

 plants are also attacked. 



Control 



for D. soror and D. 12-punctata should be used in combating this 

 species also. 



Fig. 264. — The Western 

 striped cucumber beetle, 

 Diabrotica trivittata Mann. 

 A.dult srreatlv enlarged. 



Control measures as recommended (Original) 



THE GREEN DOCK BEETLE 



(Idstroidea cyanea Melsheimer 

 (Gastroidca cwsia Rogers) 



(Fig. 265) 



Description. — The beetles are metallic green or bluish above and 

 black beneath. The legs and antennae are also black. The length of 

 the females averages about i\ inch and the width £ inch. The males 

 are slightly smaller. The eggs are bright yellow or orange, regularly 

 oblong, T \r inch long and laid in clusters of from three to fifty or even 

 more. The first hatched larvae are dull-green with body tubercles and 

 beads black. The mature forms are black and attain ■} inch in length. 

 The pupae are bright yellow at tirst, becoming darker with age. 



Life History. — The adults hibernate and emerge in great numbers 

 in March and April. They feed extensively before egg laying, which 

 begins about the first of April. The eggs are laid in masses, usually 

 upon the host or upon nearby plants, and hatch in a few days. The 

 larvae begin at once to feed upon the foliage and mature in two or 

 three weeks. Pupation takes place in the soil and requires but two or 

 three weeks. There appears to be but one large brood a year, though 

 the shortness of it would indicate at least a second small brood. 



Nature of Work. — The larva 1 and adults feed upon the leaves of 

 the host plants, eating around the edges or making irregular holes 

 throughout or even devouring all of the foliage. 



Distribution. — This beetle is a very common insect throughout the 

 State. 



