INSECTS 



Fig. 107. A dead potato 

 aphis that has contained a 

 parasite, which when adult 

 escaped through the door cut 

 in the back of the aphis 



home. The guest that so 

 ravishes its protector is 

 the grub of a small wasp- 

 like insect (Fig. 108) with 

 a long, sharp ovipositor 

 by means ot which it 

 thrusts an egg into the 

 body of a living aphid 



on almost any plant, you will 

 most likely note here and there 

 a much swollen aphid of a brown- 

 ish color. Closer examination 

 reveals that such individuals are 

 dead, and many of them have a 

 large round hole in the back, 

 perhaps with a lid standing up 

 from one edge like a trap door 

 (Fig. 107). These aphids have 

 not died natural deaths; each 

 has been made the involuntary 

 host ot another insect that con- 

 verted its body into a temporary 



Fig. 108. Aphidius, a com- 

 mon small wasplike parasite of 

 aphids 



Fig. 109. A female Aphidius inserting an 

 egg into the body of a living aphis, where 

 the egg hatches; the larva grows to ma- 

 turity by feeding in the tissues of the 

 aphis. (From Webster) 



(Fig. 109). Here the egg hatches 

 and the young grub feeds on 

 the juices of the aphid until it 

 is itself hill-grown, by which 

 time the aphid is exhausted and 

 dead. Then the grub slits open 

 the lower wall of the hollow 

 corpse and spins a web between 

 the lips ot the opening and 

 against the surface of the leaf 

 below, which attaches the aphid 

 shell to the support. Thus se- 

 cured, the grub proceeds to give 



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