June, '11] PEMBERTOX: CHRISTMAS-BERRY TINGIS 339 



maximum was six and the minimum three, average four and one- 

 half. During July the maximum was five and the minimum two,, 

 average three and one half. In August two days seemed to be 

 general' y required. 



From individual counts it was found that the average number of 

 eggs deposited in May was twenty while in July and August it was 

 twenty-five to thirty. 



Very soon after molting the last time the adults began laying eggs. 

 and from two to six were deposited each day until toward the last 

 when a day or two passed without eggs being deposited. The life of 

 the adult averaged about- fifteen days, although one individual lived 

 for twenty-six days. The average time required to reach the adult 

 stage after hatching was twelve days, wth the maximum twenty-twa 

 and the minimum seven. 



THE CALIFORNIA CHRISTMAS -BERRY TINGIS 



By C. Pemberton, Stanford University, Californin 



The plant that takes the place in California of the holly of the East, 

 as far as this place can be taken at all, is the so-called Christmas-berry, 

 Heteromeles arhutifoha. By the first of December the shrubby bushes 

 of this native plant are laden with firm, bright-red berries which are 

 not at all unlike the holly-berry in appearance and are much used 

 for holiday decoration. But not every year are the berries well 

 developed and bright and in any year not all the bushes are equally 

 strong and fruitful. 



Among the causes for these failures of the bushes to reward the 

 berry-gatherer, a small sap-sucking insect is not the least important. 

 This insect may be called the California Chirstmas-berry tingis. 



It is probably the same species as the Eastern hawthorn tingis, 

 Corythuca arcuata, but it differs from this Eastern form so plainly and 

 constantly by its paler color and disappearing pattern spots that it 

 must certainly be recognized as a distinct variety of the species. 



The species is common on hawthorn in the eastern United States 

 and also on the apple and hawthorn in western Washington where it is 

 probably an introduced insect. 



The presence of the pest on the Christmas-berry can easily be de- 

 tected by the brown, sun-burned appearance of the under sides of the 

 leaves. This drying and mottling are due to the punctures and loss 

 of sap and also to the presence of the excrement and dried cast-skins 

 of the nymphal stages. When the attack is a bad one, as it often is. 



