STATE HORTICULTUKAL SOCIETY. 305 



if next year should prove to be as favorable to plant-lice as the past we probably 

 will find the species to be greatly on the increase. 



The poplars of this locality are also affected by several gall-inhabiting species 

 that not only do great injury to the trees, but also makes them unsightly as shade 

 trees. This is especially the case with the vagabond gall lonse (Pemphigus vaga- 

 bundus, Walsh), found not only on the poplar but also on the cottonwood, as large, 

 irregular cocks-comb galls on the ends of tbe twigs, greatly injuring and deform- 

 ing the tree by stopping all growth of the twig thus affected. And as the galls re- 

 main over winter and turn black, they make the tree quite unsightly after the 

 leaves have fallen. On University Avenue, we have a group of trees that are lit- 

 erally covered with these galls, hardly a twig being found that does not end with 

 one. 



Two other species are found to make their galls on the stalk of the leaves, but as 

 these are smaller and fall with the leaves they are less objectionable. 



The following paper by R. J. Mendenhall, of Minneapolis, was placed 

 on file: 



USEFUL INSECTS. 



By R. J. Mendenhall, Minneapolis. 



Mr. President and Horticultural Friends : 



In the talks that we have had from year to year on the subject of insects, I have 

 called your attention only to the pernicious caterpillars, worms and grubs from 

 which we, as gardeners and fruit-growers, suffer every. year more or less loss, I 

 think now, in justice to xhe "bug" community, that I ought to say a few words on 

 the other side, and introduce to you, instead of enemies, a few of the more import- 

 ant of our eix-legged friends. 



When we come to count them up we find that the "good bugs," in point of 

 numbers and value of services rendered, very nearly balance the "bad" ones, and 

 that if the former were all to be suddenly exterminated we should find ourselves, 

 in spite of our "insect powders," "emulsions" and "spraying machines," quite 

 powerless to protect our fruits, flowers and vegetables against the destructive 

 species. Those that I have called "good" are such from a human point of view 

 only, and because they assist man — not by any means, however, from motives of 

 benovelence toward him— in keeping in check the species that do him most damage. 

 By their own kind, there is every reason to believe, they are regarded with terror 

 and abhorence, as the most ferocious and greedy of murderers and cannibals and 

 very likely they are "oul-lawed" by every first-class insect community. 



The insects that have proven themselves useful to us in the manner indicated, 

 may be divided into two classes, the predatory or hunting species and the true 

 parasites. In the first class will be found the Tiger beetles, the various ground 

 beetles, the Water-tigers, the larvae of the Lady birds or Lady bugs, the various 

 sorts of Soldier bugs and the larvae of the lace wing flies and some few other Nerve- 

 winged species. Most of the true parasites are found among the two- winged or 

 four-winged flies. 



The Tiger beetles and Ground beetles are the tigers, leopards, lions and cats of 

 20 



