314 SOME INSECTS OP ECONOMIC IMPORTANCE. 



winter and in spring they emerge and egg deposition 

 takes places (Fig. 168). 



The larva is known as a wireworm and is a very destruc- 

 tive pest. It grows to nearly an inch in length, and is of a 

 yellowish colour. .The three pairs of thoracic legs are 

 very short, and there is a pair of very rudimentary feet 

 upon the last segment of the body. These wire worms 

 have biting jaws with which they attack the underground 

 steins and roots of cereals and various 

 other crops. They live a long time 

 in the soil, the larval period extend- 

 ing from three to five years, conse- 

 quently they are capable of doing 

 very great damage. The pupal stage 

 lasts only a few weeks (Fig. 169). 



Lapwings, jackdaws, rooks, and 

 starlings are amongst the chief 

 natural enemies of the wireworms. 



Both beetles and wireworms should 

 be collected and examined. The 

 latter are good examples of true 

 grubs. 



An important point to note in 

 connection with attacks of these flies 

 is that the larva is the active in- 

 jurious agent. There are insects 

 which attack onions, carrots, man- 

 golds, celery, cabbage, etc. ; in each 

 case a distinct species of maggot 

 feeds upon the plant. 

 In cases of insect attack upon field or garden crops the 

 recognition of the larval type is therefore of importance. 

 The presence of maggots indicates a fly as the insect type 

 which lays the eggs upon the plant. In all cases of doubt 

 the larvae should be reared in captivity and the adults 

 captured for examination when they hatch out. 



