24 BULLETIN 190, UNITED STATES NATIONAL MUSEUM 



It is an excellent account and a credit to the author's keen observations. 

 The food plant cited is Polygonum paronychia, a prostrate perennial at 

 Lake Merced in the San Francisco suburbs. When I visited this locality 

 in recent years, I found it had undergone drastic changes by incorpora- 

 tion into the city parks, and so Williams's experiences could not be re- 

 peated. Examples of the Lake Merced series bred by Williams and 

 submitted by the California Academy of Sciences are typical polygoni. 

 We do not know^ whether this holds true for the w^hole series. The 

 Academy Museum has a large accumulation of buckwheat root borers 

 from various Pacific coast regions, rich in forms and varieties, but lacking 

 in data on food plants and habits. On Twin Peaks in San Francisco 

 proper the work of a borer in the roots of a low-growing species of 

 Eriogonum was observed, duplicating exactly the description by Williams 

 of the root borer in Polygonum at Lake Merced. Imagoes were not 

 obtained, however. 



My food-plant records are confined entirely to species of Eriogonum, 

 all plants of shrubby growth and with hard, woody rootstocks. These 

 plants are prominent in the floral display of central and southern Cali- 

 fornia, covering sandy flats and steep hillsides with a pinkish hue during 

 the summer flowering season. This abundance of food plants, however, 

 does not indicate an abundance of the insect. The borer appears to exist 

 in colonies, rather scattered, often widely apart. Where present the 

 larvae throw out small, reddish pellets, easily seen as they accumulate 

 around the top of the roots. The larval galleries extend 3 or more 

 inches down into the root and sometimes upward for a short distance in 

 a stem of the plant above ground ; they are largely filled with pellets of 

 frass, with about 1 inch left clear for pupation, this portion being silk- 

 lined and having a thinly covered exit at the upper end. The moths 

 appear from late in March to July or even later at high elevations. They 

 are strong fliers, and away from their breeding places stray examples 

 may be encountered anywhere from sea level to above timberline. They 

 frequently visit flowers. This habit led authors to name them for plants 

 on which they were captured, a procedure not to be recommended, except 

 when the plant has been proved actually to be the host. Thus, the name 

 polygoni applies very well, while such names as achillae, eremocarpi, 

 orthocarpi, and helianthi are misleading. 



The conclusions given here regarding polygoni, the typical form and 

 its color variations, are based on long series of reared examples, aug- 

 mented by large numbers of specimens captured throughout the range of 

 the species. Additional breeding experiments by T. W. Hower, of 

 Orange, Calif., and by C. Henne, of South Pasadena, Calif., have given 

 identical results. All told, several hundred specimens have been ex- 

 amined. A number of species of the plant genus Eriogonum serve as food 

 plants. In California E. jasciculatum and in Arizona E. zvrightii are found 



