PROCEEDINGS OF TWENTY-SIXTH FKUIT-GROWERS' CONVENTION. 167 



from which they were driven. They thus appear to brood over the eggs, 

 which, together with the whitish powder already referred to, form a nest 

 in which the mother sits. Other species move about considerably, and 

 lay only one or two eggs upon a leaf. 



The Young Insect. — Upon hatching, the young insects very soon 

 select a place upon a leaf and insert their beaks. They walk about 

 much less than do the young scale insects, scarcely ever leaving the leaf 

 upon which they hatch. Like scale insects, when once settled they are 

 very loath to move, and in some species are entirely unable to do so, 

 except at the moulting period. Thus, they become full grown and 

 transform into adults, in most cases, upon or near the spot where they 

 took their first meal. The insect in this stage is always very flat, oval 

 in outline, in color usually either jet black or of a uniform pale-green 

 tone like that of the leaf. The white-fly of the orange is one of the green 

 species, and, being cemented fast to the leaf by its own secretions, is 

 quite difficult to recognize, except upon very close inspection of the 

 leaf. All members of this group secrete more or less waxy material, and 

 in this case the wax when produced is fluid enough to accomplish this 

 firm attachment of the body of the insect to the leaf. One of the com- 

 monest species in California, the one that feeds upon the common sow 

 thistle, is also of this green color, but not so firmly fastened to the leaf. 



The openings of the breathing system of these insects are always on 

 the underside, quite a distance from the edge of the body, but communi- 

 cative with the outside air by means of curiously developed grooves on 

 the underside of the body, which remain open after the insect is fastened 

 to the leaf. There are three of these grooves — one at the hind end of 

 the body, and one on either side just back of the head. There is usually 

 a slight difference in coloration along these lines, so that they can be 

 clearly recognized from the upper side, because of the transparency of 

 the body. 



In the black species the wax is usually of a brilliant white, contrast- 

 ing sharply with the general color of both the leaf and the insect, 

 making the latter an extremely striking object. Sometimes this waxy 

 secretion is in the form of a fringe, more or less matted together, 

 extending around the insect along the extreme edge of the body. This is 

 the case in the Aleurodes which has recently been found in destructive 

 quantities upon grapevines in the northern coast counties. 



There are numerous parts of the body upon which waxy glands may 

 be developed. One of the most beautiful species that occurs in this 

 State is found upon our common live oak. In this case the wax is not 

 upon the extreme edge of the body, but projects up from the back in 

 the form of broad, white flakes, of a very definite and regular shape. 

 In this insect there are three small but very active wax glands, situated 



