248 MANUAL OF NATURAL HISTORY. 



4 FAMILY. Blight-Flies (Psyllidge). Antennae 

 moderate, filiform, 10-jointed, inserted in 

 front of eyes ; head deeply cleft in front ; 

 eyes lateral, prominent ; ocelli three, on top 

 of head ; proboscis short, 3-jointed ; wings 

 deflexed at sides of body, the fore-wings 

 with three strong, furcate nerves ; hind- 

 legs fitted for leaping, with two strong 

 spurs. Live upon plants; often produce 

 galls. 



5. FAMILY. Plant-Lice (Aphididse). Antennae 



moderate, 7-jointed ; head entire in front ; 

 eyes moderate ; ocelli three, on top of head ; 

 proboscis long, perpendicular or inflexed ; 

 wings greatly deflexed in repose, the hinder 

 with strong nerves ; legs long and slender, 

 formed only for walking. Females often 

 apterous ; body sometimes clothed with a 

 white cottony secretion ; live in society on 

 various plants. 



6. FAMILY. Mealy-winged Scale-Insects (Aley- 



rodidae). Antennae short, 6-jointed; head 

 small ; eyes bipartite ; proboscis short, 2- 

 jointed ; wings broad, oval, of equal size, 

 covered with a white powder, nearly hori- 

 zontal in repose, the anterior with only 

 one strong central nerve ; abdomen simple 

 at tip ; legs short, simple ; larva scale-like. 

 Both sexes with four wings in perfect state ; 

 feed on leaves of plants. 



