204 



INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



surface and 1-20 inch long-. They are deposited on the spines in rows 

 of from twelve to fifty. The young are brownish or nearly black with 

 light green or reddish abdomen. 



Life History.— The adults hibernate under any shelter near the 

 cactus plants and emerge to begin breeding early in the spring. The 

 eggs are laid on the spines, each 

 female laying from thirty to forty. 

 The species feeds mostly at night in 

 colonies on the joints of the cactus, 

 producing light spots on the surface 

 of the host. Breeding continues 

 throughout the year, there being sev- 

 eral overlapping generations. 



Nature of Work. — The joints are 

 the points of attack and the injury, at 

 first appearing as small yellow spots, 

 continues until the tissues become 

 brown and deadened and the joints so 

 weakened that the plants fall over. 

 Some of these take new root, while 

 many dry up and never recover. The whitish excrement of the bugs is 

 always associated with the work and is a means of determining the 

 cause of the damage. 



Distribution.— This bug is widely distributed throughout the south- 

 ern part of the State and the more arid regions of the southwestern 

 portion of the United States. 



Food Plants.— The various species of Opuniia are attacked and 

 much damage is done to the plants. With the utilization of the spine- 

 less cactus as a forage plant the insect under discussion is likely to 

 become better known. 



Control. — Control measures which might be suggested for trial con- 

 sist in destroying all possible rubbish under the plants to force the 

 adults to seek hibernation' elsewhere and the application of contact 

 sprays (tobacco decoction and soap or oil emulsion) when the young 

 appear in the spring of the year. 



Fit;-. ISO. — The cactus-joint bus'. Chr- 

 linidea tabulata Burm. Adult and 

 nymph. Enlarged twice. (Original) 



THE BOX-ELDER PLANT-BUG 



Leptocoris trivittatus (Say) 



[Serinetha trivittata (Say)] 



(Lyffwus trivittatus Say) 



(Fig. 181) 



Description. — The very young forms are bright red and when about 

 half-grown they become marked with black. The adults are dull-black 

 with red markings on the body and wings, as shown in Fig. 181. The 

 average length of the females is nearly i inch, and the width one third 

 as much. The males are somewhat smaller. 



Life History.— The adults hibernate in sheltered places and emerge 

 early in the spring, as .soon as the buds burst, to lay eggs which soon 

 Hatch into the small red young. These feed upon the foliage of the 

 box-elder and mature within a couple of weeks. By the middle of 



