Rural School Leaflet 



903 



Fig. 4. 



-Syrphus fly, enlarged and natural 

 size 



man}^ ants in quest of the honeydew. The ants obtain the sweet material 

 in an interesting way, and the whole process can be seen by patient, carefiil 

 watching. An individual ant walks 

 up to an aphid and strokes the latter 

 with its antennas, or "feelers," to 

 which the aphid responds by giving 

 out a drop of the honeydew. This 

 action may be repeated with 

 three or four of the aphids until 

 the ant has all that it desires, 

 when it hurries down the stem of 

 the plant and away to its nest 

 with its load of sweet provender. 

 In return for these supplies of 

 delectable food, the ants protect 

 the aphids from their enemies and 

 sometimes actually build cover- 

 ings, or "sheds," over the aphids. More remarkable still, sometimes the 

 ants carry the eggs of the aphids into their nests in the fall and care for 

 them most solicitously through the winter until they hatch in the spring; 

 then the ants take the young aphids and carry them out tenderly, placing 

 them on favorite food plants where they can thrive and produce honey- 

 dew again. 



On the other hand, aphids have their enemies as well as their friends, 

 and their enemies are legion. One of the worst enemies of aphids, and 



at the same time one of the most effec- 

 tive forces in keeping plant lice under 

 control, is the ladybird beetle. At least 

 eight different kinds of ladybirds prey on 

 plant lice and aid in holding them in check. 

 In a badly infested field of cabbages one 

 is almost sure to find many specimens of 

 the convergent ladybird, the thirteen- and 

 fifteen-spotted ladybirds, and other kinds, 

 all doing valiant work in destroying the 

 cabbage lice. 



Then there are the syrphus flies (Fig. 4) 



that lay their conspicuous white eggs 



(Fig. 5) right among the colonies of 



aphids. When the eggs of the syrphus 



flies hatch, the larvae find themselves in the midst of living aphids, which 



prove very acceptable as food. One larva of a syrphus fly will devour 



Fig. 5. — Eggs of syrphus fly 



