3 1 



The adults are frequently seen in coitu, but probably many eggs 

 are unfertilized. Before pairing, there seem to be certain prelimi- 

 nary movements. The male takes a position alongside of the female, 

 intermittently flaps its wings and at the same time continually strokes 

 with its own antennae the nearest antenna of the female. Their 

 position is well illustrated by Davis (17). Frequently two males, one 

 on each side, thus court a female. If the suit is successful, the 

 female slightly raises the tip of the abdomen, at the same time the 

 male taking a position of about thirty or forty degrees with the body 

 of the female, with its inner wings arising above those of the female, 

 bends the tip of its abdomen upward, and clasps the genitalia of the 

 female from below. 



Egg Laying. The female seems to have no choice of position 

 on a plant for deposition of eggs, but leaves them wherever she may 

 happen to be feeding. Eggs are not uncommonly found on the upper 

 surface of the leaves, on the petioles and even on the stems of the 

 plant, though the great majority are found on the favorite feeding 

 place of the adults — the under surface of the leaf. The adults prefer 

 the youngest leaves, and there is a slow but continual migration up- 

 ward to keep pace with the unfolding of the leaf buds, the majority 

 of the freshly laid eggs being found, therefore, on the upper leaves 

 of a plant. The female frequently, as has been observed by pre- 

 vious writers, uses her rostrum as a pivot, and deposits her eggs in 

 a more or less complete circle about her. From ten to twenty eggs 

 are often found in one of these circles, which are about 1.5 mm. in 

 diameter. Eggs are also deposited singly, this being the case es- 

 pecially on hairy leaves. The writer has observed as many as twelve 

 thousand eggs per square inch on the under surface of a Salvia leaf 

 with more being constantly added. The eggs, however abundant, 

 never touch one another, it being probably impossible for the female, 

 on account of the conformation of the ovipositor and the end of the 

 abdomen to deposit eggs so close to one another that they are 

 actually in contact. 



Observations on the duration of adult life, parthenogenesis, etc. 

 Adult females have been isolated on plants previously free from 

 Aleyrodes in any stage, for the purpose of determining the duration 

 of adult life, the number of eggs laid by each female, whether or not 

 parthenogenesis occurs, and if so, its character. The females iso- 



