XXIV EXPLANATION OF THK PLATES. 



a Setae withdrawn. b the setae projecting. 



c Seise separated into three parts, the outer of which correspond to the jaws 

 of insects, the middle one to the tongue. It is by this apparatus the insect pierces 

 the cells of the plant, which enables it to suck the juices. 



PLATE IX. 



APHIS VASTATOR. 

 All the figures are magnified except the leaflet. 



FIG. 1. Aphis vastalor in the winged state. 



2. Under side with rostrum in situ. 



3. One of the antennae carefully drawn with the camera lu- 

 cida. 



4. Perfect insect, showing the manner in which it carries its 

 wings in a state of repose. 



5. Aphis vastator in which an ichneumon had deposited its 

 eggs, and from which the perfect parasite has escaped through 

 the aperture shown in the dorsum. 



6. Leaflet (natural size), showing its appearance when co- 

 vered by the vastator. For perspicuity the antennas are all 

 shown projecting in front, whilst in reality they are reflexed when 

 the insect is feeding. 



PLATE X. 



DESTROYERS OF APHIDES. 



FIG. 1. Psen equestris. 



2. Diodontis gracilis. 



3. Cynips. 



4. Aphidius rapae. 



5. Larva of Chrysopa perla. 



6. Chrysopa perla. 



7. Larva of Scaeva pyrastri. 



8. Pupa of Scaeva pyrastri. 



9. Scaeva pyrastri. 



10. Larva of a Coccinella. 



