270 



[NJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



THE WESTERN TWELVE-SPOTTED CUCUMBER BEETLE 

 Diabrotica soror Leconte 178 



(Fig. 261) 



Description. — Tli is beetle is easily recognized by its bright green 

 wing covers, which are spotted with black, as shown in Fig. 261. The 

 prothorax is green or yellowish, the head, antennas, legs and body black. 



The average length of 

 the females is nearly 

 | inch; the males are 

 somewhat smaller. 

 The eggs are dull yel- 

 low, elongated, with 

 one end slightly 

 larger, finely sculp- 

 tured surface and 

 about 1-38 inch long. 

 The larvas are white 

 with yellowish o r 

 brownish head and 

 about 1 inch long 

 when full-grown. The 

 pupa 1 are white or 

 yellowish until nearly 

 ready to transform 

 into adults, when they 

 gradually assume the 

 color of the latter. 



Life History. 1 *" — 

 Many of the adults 

 hibernate and begin 

 feeding early in the 

 spring, when egg-lay- 

 ing begins (March to 

 May). The eggs are 

 laid singly or in 

 masses of from four 

 or five to fifty about the bases of food plants, from £ to | inch below 

 the surface of the ground. The larva; feed upon the roots. When full- 

 grown they form earthen pupal cells near the surface of the ground, 

 where pupation takes place, and in about two weeks the adults emerge. 

 There are probably at least two broods a year. 



" 8 Key to California species of Diabrotica. 



a. Wing covers or elytra green with black spots 1>. 



Wing covers or elytra light yellow with three black longitudinal stripes 



trivittata Mann. 



b. Under side of body light yellowish or greenish, at least portions of legs and 



antennae light o. 



Body, legs and antennae black throughout soror Lea 



C. Black spots on elytra pronounced and fairly constant; first 3 articles of 



antennae and bases of femora light ; remainder black 12-punctata Oliv.' 7 " 



Black spots on elytra indistinct, exceedingly variable or often entirely 



obliterated, entire legs and antennae yellow, green or light brown 



12-punctata tenella Lee. 



7 This species does not occur in this State, according to Dr. Van Dyke. All records 

 regarding it refer to other species. 



'••Chittenden, F, IT., Bui. No. 82, Pt. VI, Bur. Ent. U. S. Dept. Agric ., pp. 71-7. r >, 1010. 



Fig. 261. — The Western twelve-spotted cucumber beetle, 

 Diabrotica soror Lee. Adults and their work on watermelon 

 leaf. Slightly enlarged. (Original) 



