fruits, strawbeiT}^, and purslane — but it attacks also clover, beans, 

 beets, spinach, tomato, hops, and pear, and several ornamental plants, 

 including' hydrangea, begonia, ground ivy {Nepeta glechoma)^ Aca- 

 lypha, and morning-glor}'. From its abundance on some of these 

 plants it has received a number of common as well as Latin synonym- 

 ical names, the former including cotton aphis, orange aphis, cucumber 

 louse, and cantaloupe louse/^ It is frequently called also the "black 

 aphis," especially in its occurrence in greenhouses. Mr. Pergande has 

 found it feeding upon a large number of weeds, among which are shep- 

 herd's purse, pepper-grass, pigweed (Amaranth us), dock (Rumex), bur- 

 dock (Arctium), dandelion, lambsquarters (Chenopodium), plantain, 

 chickweed, button-weed (Diodia), mallow, dogwood (Cornus), and 

 Jamestown or jimson weed (Datura). 



Since these aphides are not at all particular as to their food, when 

 they migrate from their favorite plants they start colonies on nearly 

 any plant that chances to be in their line of flight. The writer has 

 seen asparagus and violet attacked, the latter grown in greenhouses. 



LIFE HISTORY. 



Attack to cultivated plants begins from early spring till consider- 

 abl}^ later, and is made by winged individuals fl3^ing from weeds which 

 serve as alternate food plants. Infestation naturally commences earlier 

 in the South than northward, and may be simultaneous with the appear- 

 ance of the crop above ground. Soon after the plants have developed 

 leaves a few winged aphides can usually be found, and these are the 

 forerunners of myriads to follow. As often as a plant becomes 

 exhausted of its vital juices by the sucking mouth-parts of innumera- 

 ble aphides, winged individuals are developed which migrate to other 

 plants, so that migration in the case of this species is carried on prac- 

 tically thruout the season. Flight from one kind of food plant to 

 another, or from one field to another, is caused also by disturbance 

 from the abundant natural enemies of the insect. The great num- 

 bers of this species sometimes suddenly discovered on melons, cotton, 

 orange, and. other plants are often due to enforced migration on account 

 of the death of other food plants in the vicinity, such as might be 

 caused by atmospheric conditions, or by the ravages of the aphides 

 themselves, or of other insects. The removal of the crop on which 

 the insect was at work will produce the same efi'ect. 



NATURAL ENEMIES. 



There is perhaps no better example, among insects, of a common 

 and widespread species being held in abeyance and limited to innoxious 



« The synonyms include Aphis {Siphonophora) citrifolii Ashm., ApMs citrulli Ashm., 

 Aphis cucumeris Forbes, Aphis forbesi Weed. It is still mentioned in literature as 

 A. cucumeris. 



