THE STATE ENTOMOLOGIST. 7 



fact connected with this insect has been developed this year by Dr. 

 E. S. Hull, the able Illinois State Horticulturist, which is of such im- 

 portance that I cannot pass it over even in this brief report. He has 

 ascertained that we suffer from the injurious punctures of their little 

 beaks long after the lice themselves have disappeared. In fact, he 

 has proved to his own satisfaction that the so-called" scab" in apples, 

 which prevailed to such an alarming extent last year, and rendered 

 thousands and thousands of bushels valueless for market purposes, is 

 actually caused by the punctures of these lice. I said that the doctor 

 had proved this matter " to his own satisfaction," because I believe 

 that caution requires that we should not consider it as an established 

 fact until all objections to it can be dispelled. Personally I have 

 made no observations on this matter, but the facts in the case all add 

 weight to Dr. Hull's theory, if such it can be called. Hitherto the 

 cause of the " scab" on apples has been involved in mystery. 

 It was supposed to have a fungoid origin ; yet an examination will 

 show that the scabby appearance is not caused by any live fungus, 

 but by arrested growth of the cells which have become corky and 

 cicatrized. The importance of this discovery of Dr. Hull's, should it 

 once be firmly established, cannot well be estimated; for when we 

 have once ascertained the cause of a disease, it need scarcely exist 

 any longer. By destroying the lice we shall prevent scabby apples, 

 and experience teaches that they can be destroyed by a good syring- 

 ing of tobacco-water. We may expect, in this immediate vicinity, 

 an almost total exemption from "scab" next year, for the apple trees 

 are remarkably free from the minute black bead-like eggs of the 

 Plant-louse with which they were so thoroughly peppered a year ago. 



The Tent Caterpillar ( Clisiocampa Americana) was more abund- 

 ant than usual in our orchards, and the Tent Caterpillar of the Forest 

 ( Clisiocampa sylvatica) also appeared in great numbers both on our 

 orchard and forest trees. 



A worm which I have called the Pickle Worm, (Phacellura niti- 

 dalisi Cram.) and which had never been publicly noticed before, ap- 

 peared in immense numbers, and did great damage to our cucumbers 

 and melons by boring into the fruit, but as this insect, with others, 

 will be fully treated of in my forthcoming Report, I will pass on to 

 a more general subject. 



"The pebble in the streamlet scant, 



May turn the course of many a river ; 

 The dew-drop on the infant plant, 



May warp the giant oak forever." 



In no department of science does the old proverb "prevention is 

 better than cure," apply with such force as in that of Economic Ento- 

 mology. In my gtudies and observations I have often been struck 

 with the fact that many of our very worst insect enemies have been 

 introduced from abroad, and that if this subject of Economic Ento- 

 mology had been better understood and appreciated fifty years ago, 



