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Anions: the insects whose life histories have been studied are 

 several species of wire-worms, a millipede very destructive to 

 melons, a considerable number of insects injurious to forest and 

 shade trees, two previously undescribed insects infesting roses to 

 an injurious extent, several pests of hot-house plants, and those 

 insects injurious to fruits described in our bulletins on this subject. 



The most extended of our experiments with insecticides have 

 been those upon wire worms already referred to. The results of 

 these experiments have been rather discouraging, being almost 

 entirely negative. We are delaying the publication of these re- 

 sults in the hope that we shall soon be able to discover some prac- 

 ticable way of combating these pests. But we shall not delay 

 much longer ; for we feel that even our negative results are im- 

 portant ; as they indicate the futility of nearly all of the commonly 

 recommended methods of fighting these pests. For example, we 

 have determined that our most common species of wire-worm can- 

 not be destroyed by the use of salt in quantities not injurious to 

 field crops. Although this knowledge does not aid us in combat- 

 ing the wire- worms, it will save the wasting of salt in a futile 

 effort to destroy these insects.* We have also demonstrated the im- 

 practicability of starving wire-worms in the soil by sowing either 

 buckwheat or mustard as has often been recommended, or even by 

 starving them by clean fallow. These conclusions have been 

 reached by a large number of experiments, the details of which 

 will be published later. 



In our studies of the life history of wire-worms, an interesting 

 point was determined, which is of some practical importance, and 

 will therefore be mentioned here. Wire- worms live for several 

 years in the worm or larval state. When the worms are fully 

 grown they change to pupae. This takes place in the species that 

 commonly infests field crops during the summer. The pupa state 

 lasts only a short time, the insect assuming the adult form in the 

 latter part of the summer. But, strange to say, although the adult 

 state is reached at this time, the insect remains in the cell in the 

 ground in which it has undergone its transformations till the fol- 

 lowing spring, nearly an entire year. With most insects only a 

 very short time is required, after the change from the pupa to the 



* It is possible that the use of salt results beneficially by driving the 

 worms deep into the soil and thus giving the youug plants a chance to 

 start. Experiments will to tried to test this point. 



