THE MONTHLY BULLETIN. 



45 



feed. These larvte vary from lirown, yellow, or orange to dark green 

 in color, according to the species. They are true maggots, with one end 

 bhnit and the other pointed. In feeding, they clasp their support by 

 the blunt end, lift the plant louse bodily into the air with the pointed 

 end and suck out the juices. The most common adult insects have 

 yellow bodies with dark transverse stripes across the abdomen. The 

 small syrphid {Allograpfa obliqua Say), the very large syrphid 

 {Lasiophthicus pyrastri L.) and Sijrphus amencanus Wied. are com- 

 mon in California. 



Coccinellidce. The work of the ladybird beetles on plant lice is known 

 to all. The red ladybird beetles {Cydoneda sanguinca Linn., and Cocci- 

 nclla calif ornka Mann.), the black-spotted ladybird beetle {Hippo- 

 damia convergens Guer.). Hippodamia amhigua Lee, Megilla maculata 

 DeG., the eyed ladybird {Olla oculata Fab.), OUa ahdominalis Say and 

 the two-spotted ladybird {Adalia Upunctata Linn.) are the most com- 

 mon California species. 



Chrysopidcv. One of the most common insect predators, preying on 

 all sorts of soft-bodied insects, is the common green lacewing, called 

 aphis lion because of its destructiveness to all plant lice. The eggs, 

 larvffi, pupte and adults are to be found everywhere in the fields, woods 

 and orchards; wherever there are infestations of plant lice. In the 

 orchards of California they are very abundant and play an important 

 part in the control of many bad pests, but more important in keeping 

 down the aphids. When there is no prey in the orchards they go to 

 the fields and brush to seek other game and return as soon as the lice 

 begin to appear. 



Internal Parasites. 



Internal parasites are those which develop within the body of the 

 host. The adult female, by means of a sharp ovipositor, deposits her 

 eggs within the bodies of the lice. These eggs hatch, and the resulting 

 young develop into legless, maggot-like individuals which live on the 

 body juices of the aphids, thereby completely destroying them. When 

 fully developed, a small hole cut in the backs of the lice liberates the 

 adults, which immediately attack other living lice. 



To these parasites, more than to all others, is due the credit of com- 

 pletely controlling many aphids which would otherwise become very 

 destructive. They do not usually get in their work until rather late in 

 the season, after the aphids have done most of their damage, but though 

 late, it is sure. Though the natural enemies are very efficient in a 

 majority of cases, yet all of the real pests (pests because they are not. 

 so held in check) must usually be controlled by artificial methods, of 

 which spraying is recognized as the most efficient. 



Artificial Methods of Control. 



Sprays. Treatment for insects which are both aerial and subter- 

 ranean in habits naturally calls for entirely different methods for each 



