ENTOMOLOGY 263 



Aphididae. The color of the species varies greatly, ranging from 

 almost yellow to nearly black, but the prevailing color noticed by the 

 writer is a more or less purplish green. Like the other aphid pests 

 of greenhouses, this species increases very rapidly, and if neglected 

 soon injures its host. The lice confine themselves principally to the 

 under side of the leaves of the cucumber, but those found upon the 

 begonias and Hibiscus were attacking the flower buds and terminal 

 shoots of the plant, and entirely ignoring the leaves. The life history 

 is practically the same as that of the chrysanthemum aphis, both 

 winged and wingless agamic females being produced, and a genera- 

 tion of sexual individuals developing at intervals. The females pos- 

 sessing wings arc much more numerous in this species than for any 

 of the others found in greenhouses. 



The Brown Aphis of the Violet. The species is sufficiently dis- 

 tinguished from the green aphis affecting the violet by its color, 

 which is dark brown, both in the winged and wingless forms. The 

 winged form is still more easily recognized, because of the dark- 

 clouded venation of the wings. The insects are generally found on 

 the stems of the leaves well down towards the crown, where they are 

 not readily seen, and where they are difficult to reach with any kind 

 of spray. Their injury is rather a stunting of the plant, causing it 

 to produce weakly and imperfect flowers, than the actual killing 

 of it. 



The Brown Aphis of the Violet. In this species, as with other 

 aphids, breeding is so rapid as to seem almost incredible. In no point 

 of its development does it differ materially from the foregoing species. 

 Winged agamic females, which produce agamic young, and enable 

 the species to spread, are developed at intervals, but seemingly with- 

 out any regularity, appearing to depend more upon circumstances as 

 regards food than upon anything else. When a plant becomes so 

 completely infested as to cause crowding among the insects, the 

 winged females appear, and in this way enable the species to survive. 

 As the wingless individuals are unable to spread to new food plants, 

 to any extent, but must remain upon the plant where born, some 

 such provision as the winged female is necessary. Otherwise the in- 

 sects would become so numerous upon the original plant as to kill it, 

 and thus the species would exterminate itself. A sexual generation 

 no doubt occurs also, but has not been observed. The species occurs 

 on no other plant than the violet, so far as known. 



The Red Spider. Notwithstanding its popular name, this pest 

 is in reality not a spider at all, but a tiny mite. For the purposes of 

 this paper it will not be necessary to go into a detailed and technical 

 description, since apparently only the one species is likely to be 

 found on greenhouse plants. In some raspects the name red spider 

 is a misnomer, as the mites vary in color from pale pinkish to almost 

 black, depending upon the age and food plants of the individuals. 

 Some specimens are even greenish, with two or more darker spots on 

 the back of the abdomen. They are extremely small though visible 

 without the aid of a glass, but are likely to be overlooked until atten- 

 tion is called to them by the injury to the plants. Attention i.s some- 



