380 



and Watsonville, Cal., was brought to tlie attention of this Department 

 in 3891. Specimens were first sent May 22, 1891, by Mr. W. A. Gafty 

 to the Assistant Secretary of Agriculture, with the statement that 

 1,000 acres of promising sugar beets were all more or less affected 

 by the insect. Dr. Eiley sent Mr. Koebele in June to the spot, and 

 while his observations did not result in the ascertaining of practical 

 remedies, he collected material from which the accompanying figure of 

 the difi'erent stages of the insect has been drawn. On June 6 he col- 

 lected about 2,000 eggs of the insect, all before mid-day, and nearly all 

 on the underside of the leaves. All but about 10 had hatched on June 9, 

 and the remaining 10 were mature the following morning, indicating 

 that the insect remains in the egg state for from three to four days. 



Fig. d9.—Pegomyia viciva: a. surface of egg, very highly magnified; b, larva; c, last segment of same; 

 d, anal spiracles; c, head ;/, thoracic spiracles; jr, cephalic hooks of larva; /i, puparium; i, adult lij-; 

 k, head of adult male; I, head of female — &, h. i, enlarged, other figures still more enlarged (original). 



On June 7 two plants, which Mr. Koebele had brought to his home in 

 Alameda, were cleaned of all larvae and stocked with unhatched eggs. 

 On June 8 the young larv?e began to mine the leaves, and by June 11 

 had become nearly full grown. They did not transform to pui)aria, 

 however, until June 16, making the length of the larval state to be 8 

 days, which, however, is probably shortened under perfectly natural 

 conditions. While in the field he also collected about 300 larvfe, most 

 of which pupated on June 8. The first flies issued June 28 and the 

 remainder the following week. We have, then, as the duration of a 

 generation, egg stage, three to four days; larval stage, seven to eight 

 days; puparium, twenty days, or about one generation per month. 



As above stated, the attention of the Department was first called 

 to the matter in INIay, when the work of the insect was already 



