August, '19] BURKE: FLATHEADED BORERS 327 



apricot a number of times. Mali is also more common in shade trees 

 and brush forests while femorata is commoner in the oaks and the 

 aspen forests of the high Sierras. Femorata occurs throughout the 

 United States and 7nali has been reported from Oregon, California, 

 Nevada, Utah, Colorado and Arizona. jMany of the published 

 records of damage bj^ femorata in the Rocky Mountains and Pacific 

 states undoubtedly refer to damage by mali. 



Both species often cause severe damage to shade trees as the fol- 

 lowing western records will show. In 1912 the writer found a number 

 of lombardy poplar trees in the High School grounds at Yreka, Cali- 

 fornia, severely injured by the larval mines of femorata. In 1915 

 Mr, Josef Brunner reported the same species destructive to small 

 black Cottonwood at Missoula, IMontana. The next year Mr. W. D. 

 Edmonston found about half of the silver maple shade trees, planted 

 in 1913 in Colorado Springs, killed by this species and Mr. F. C. 

 Bishoff reported serious injury to planted sycamores at Dallas, Texas. 

 An examination of a nursery near San Jose, California, in July, 1918, 

 showed that out of a block of 1,500 European sycamores, 2-2^ inches 

 in diameter, 258 were alread}^ dead from an attack by mali, many 

 more were infested and partially girdled and numerous others were 

 being infested by the young larvse. A row of 47 white flowering horse 

 chestnuts had 4 trees killed and 17 rendered unsaleable and some young 

 beech were in the same condition. About the same time a forty acre 

 field of red currants near HaA'wards, California, was found so badly 

 infested by this same species that the owner expected to root up the 

 entire lot and burn them. Planted maple, mountain ash, flowering 

 cherry, loquat, beech and birch in and around Los Gatos and San Jose 

 are heavily infested and many trees are killed outright. Both species 

 attack and kill the eucalyptus and appear to be becoming destructive 

 especially in the large planted groves. 



Femorata and mali resemble each other closelj' in habits, seasonal 

 history and character of work. The first evidences of an attack 

 are wet spots on the bark. Later, in some plants as the cherry, plum 

 and prune there is a strong flow of gum. In all cases the bark is apt 

 to crack and show the frass filled mines beneath. 



The eggs are flattened, oval, hght colored, ribbed, about Inim. 

 (1/25 in.) in diameter. They are laid singly, sometimes close together, 

 on the bark during June and July. Some are laid directly on the 

 exposed surface of the bark but most are flattened down into depres- 

 sions, tucked into crevices or inserted untler loose flakes or between 

 the scales. In hatching the young larva liorcs through the bottom 

 of the shell directly into the V>ark. It soon mines down to the wood 

 and winds back and forth through the outer wood and inner bark 



