156 PROCEEDINGS OF TWENTY-SIXTH FRUIT-GROWERS" CONVENTION. 



matter of its introduction, for it is equally possible that it might prove 

 as injurious with us as it has in Florida. We have quite a number of 

 representatives of this family in this State, most of which are of little or 

 no economic significance; but at least one species has, during the last 

 year, proven its ability to damage grapevines in a very serious manner. 

 The subject, therefore, of the Californian representatives of this family 

 can not fail to be of interest to our fruit-growers. 



The family Aleurodida is one of four closely allied groups which 

 have been assembled by entomologists under the name of Sterno- 

 rhynchs, the name being given because of the position of the mouth 

 apparently upon the breast of the insect. These four families are: 



First — Psyllida?, a rather unimportant family of small, active insects 

 called " Jumping Plant-Lice." 



Second — Aphidse, the largest family of the series, including all the 

 plant-lice, many species being highly injurious; the best known in 

 California being the phylloxera of the grapevine. 



Third — Aleurodidae, the subject of the present paper; and 



Fourth — Coccidse, or scale insects, the most notorious pests the Cali- 

 fornia grower has to contend with. 



The isimily thus lies intermediate between the plant-lice and the scale 

 insects; it is rather more closely allied to the latter than to the former, 

 but has many peculiarities of its own. The similarity is most evident 

 while the insects are young, indeed a young white-fly might easily be 

 mistaken for the young of a scale insect. The most striking difference 

 between the two families lies in the fact that while the female scale 

 insect is always wingless, both sexes of Aleurodes possess wings when 

 full grown and resemble each other very closely. 



The Eggs. — Insects of this family always reproduce themselves by 

 means of eggs. These are laid singly, and are attached to the leaves of 

 the appropriate food-plant by means of a rather short but very charac- 

 teristic stalk. The length of this stalk depends upon the species to 

 some extent; but all the species lay such similar eggs that it would not 

 be possible to distinguish them in this stage. If the egg of the lace- 

 winged fly was about half as large as it is, and its stalk was reduced to 

 about one third of the length of the egg or less, and slightly twisted, it 

 would resemble quite closely the egg of an Aleurodes. The color of the 

 egg is nearly white, and the leaf in the neighborhood of where it is 

 deposited is usually dusted over with a w^hite waxy secretion from the 

 mother. This secretion often forms very distinct spots, in which case 

 the eggs may be arranged somewhat in a circle, with the stalks outward. 

 The species that lay their eggs thus regularly in a circle occupy them- 

 selves a long while in the process of egg-laying, remaining for days in 

 one spot unless disturbed, and even then often going back to the point 



