mained quiet in the other direction, but only for a short 

 time. 



THE ACACIA WEEVIL IN SOUTHERN CALIFORNIA. 



By Theodore Payne, 



The Acacia Weevil (Bruchus pruininus Horn)* is now 

 quite common in Southern California, infecting the trees of 

 a number of species in many different localities. How long it 

 has been here I am unable to say, but it first came under my 

 personal observation in the fall of 1904 in some seed of 

 Acacia mollissima gathered at Santa Monica. This seed was 

 collected in the early part of September and a few weeks 

 later quantities of the weevil hatched out. 



A peculiar fact is that they do not all hatch the first season, 

 usually a few weeks or sometimes months after the seed is 

 gathered a batch of the weevil will hatch out. The next 

 year another lot will hatch and a year later still a third. 



From the appearance of the seed when gathered it is im- 

 possible to tell whether it is infected with the weevil or not. 

 The seed looks perfect but a few weeks later may be riddled 

 with holes. J"st before the insect emerges a circular marking 

 is seen on the shell of the seed, this is pushed outward and 

 the weevil appears. In the seed of Acacia podalyriaefolia col- 

 lected near Chino a short time after gathering fully fifty per 

 cent hatched out weevils. The next year perhaps forty or 

 fifty per cent of the remaining seed hatched out and still 

 later another batch of probablv fifteen or twenty per cent. 

 The largest crop is generally the first year, though in some 

 instances the first crop is light and the later ones heavier. 

 In Acacia armata collected in Pasadena quite a large crop 

 appeared the first year, the second year only a few. but the 

 third year al)Out ninety per cent of the remaining seed pro- 

 duced weevils. 



Acacia baileyana from Santa Barbara for two years ap- 

 peared to be absolutely free from the weevils, the third a 

 number hatched out and a second crop the fourth year. 



Acacia decurrens from Pasadena showed no weevil till 

 the second and third seasons. 



When the insect makes its way out of the seed it leaves 

 quite a large cavity but does not always destroy its germin- 

 ating power, if the hole happens to be some distance from the 

 germ, it is still possible for the seed to grow. The method 

 I have followed for separating the seed is to throw it into a 

 pan of water; the hollow seeds float and are skimmed ofif, 

 while the solid ones sink to the bottom. 



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