Insects in the Garden 335 



upon injurious insects and thus help to keep them in 

 check. A gardener should learn to recognize these ben- 

 eficial insects, so that he may preserve and protect them. 



Parasitic insects. Many garden insects are preyed 

 upon by other smaller insects that feed upon the living 

 tissues of their bodies. The large caterpillar that lives 

 on the tomato (and sometimes on the potato) may often 

 be seen with its back covered with small white oblong 

 bodies that at first glance may be mistaken for eggs. 

 These are the cocoons of the larvae of a very small fly 

 (one of the Braconids). The fly punctures the body of 

 the caterpillar and lays its eggs under the skin. Then 

 the larvae hatch and feed upon the caterpillar's body. 

 A caterpillar that has been thus parasitized often dies. 



Empty shells of plant lice (aphids) may often be found 

 clinging to the leaves of plants. These have been de- 

 stroyed by another kind of Braconid. The mother in- 

 sect finds an aphid and forces her eggs into its body. The 

 eggs soon hatch, and the larvae feed within the aphid and 

 kill it. The pupae form inside the aphid after it has died, 

 and when the adults develop they cut a circular opening 

 in the inclosing shell and fly out to lay eggs for another 

 generation. Wherever aphids are abundant, the shells 

 showing that the Braconids are at work on them can 

 nearly always be found. 



The lady beetles or lady bugs. Most lady bugs (or 

 more exactly, lady beetles) are very beneficial to the 

 gardener. The adults are small, nearly hemispherical, 

 and usually gayly colored with conspicuous spots. Their 

 larvae somewhat resemble tiny alligators in shape and are 

 usually spotted and covered with bristling spines. Both 



