10 



FIKST ANNUAL EEPOKT OF THE STATE ENTOMOLOGIST. 



ropeaii writers of tlie occurrence of the beetle upon flowers tlum of 

 the larva within liouses.* (The insect, in its several stages, is shown in 

 Fig. 5.) 



Fig 5. — Anthreniis scrophulari.e : a, the larva ; h, the cast skin of the hirva at molt- 

 ing; c, the pupa; d, the beetle — enlarged from natural sizes shown in accompanj'ing lines. 



The increased ravages of our introduced insects result from the new 

 conditions under which they are here placed. The relations that dur- 

 ing the lapse of centuries had grown up between them and tlieir food- 

 plants, their insect parasites, the birds and other animals that preyed 

 "upon them, whereby a balance and an interdependence had become es- 

 tablished — have all been broken up. When brought to our shores 

 they find, perhaps, more abundant food, of a character more acceptable 

 and attractive to them. But mainly, in their importation, tlieir natu- 

 ral parasites and the enemies which had kept them in subjection have 

 been left behind, and they are free to ply their destructive work and 

 to '^ increase and multiply" without hindrance or molestation, unless 

 some of our native parasites shall at length acquire the habit of ]M-ey- 

 ing upon them, and other foes discover that they are "good for food." 



3. The Large Areas Devoted to Special Crops. — The exces- 

 sive ravages of insects in the United States are largely owing to tlie culti- 

 vation of their food- plants in extended areas. We may illustrate this by a 

 reference to our apple-tree insects. Two hundred years ago not even 

 the wild crab, the earliest representative of the apple, existed in this 

 country, and consequently there were no apple-insects. Later, when a 

 few apple-trees became the adjunct of the simple homes of tlie early 

 settlers, those of our insects to which they ofEered more desirable food 

 than that on which they had previously subsisted, were obliged to 

 wing their way often for many miles in search of a tree upon which to 

 deposit their eggs. If birds were then abundant, how few of the in- 

 sects could safely accomplish such extended flights. But in the apple 

 orchards of the present day — some of them spreading in an almost un- 

 broken mass of foliage over hundreds of acres — our numerous apple 

 *Hagen, in Canadian, Entemologist, x, 1878, p. 101. 



