MAINE AGRICULTURAL EXPERIMENT STATION. 65 



BENEFICIAL INSECTS. 



(Adapted from Packard.) 



In a great variety of ways certain insects are helpful to man, 

 and are especially efficacious either in insuring his crops or in 

 destroying those insects which would otherwise devour them. 



Pollenizers of Fruit trees.. — A very important part in the pro- 

 duction of abundant crops of fruit is played by bees and other 

 honey- or nectar-gatherers, and pollen-feeding insects. It is 

 now generally acknowledged that bees, especially the honey- 

 bee, act as "marriage-priests" in the fertilization of flowers, 

 conveying pollen from flower to flower, and thus insuring the 

 "setting" of the fruit. Many wasps, as well as butterflies and 

 moths, species of pollen-eating beetles, thrips, and other insects, 

 by unconsciously bearing pollen from distant flowers, prevent 

 too close in-and-in breeding. Indeed, as Goethe said, flowers 

 and insects were made for each other. Many plants would 

 not bear seeds did not insects fertilize them. Insects are in the 

 first place attracted to flowers by their sweet scent and bright 

 colors, and it is claimed that the lines and circles on the corolla 

 of certain flowers guide them to the nectary; though we do 

 not see why the scent is not in the main sufficient for this pur- 

 pose. According to Sir John Lubbock, "The visits of 'insects 

 are of great importance to plants in transferring the pollen from 

 the stamens to the pistil. In many plants the stamens and pistil 

 are situated in separate flowers ; and even in those cases where 

 they are contained in the same flower, self-fertilization is often 

 rendered difficult or impossible; sometimes by the relative posi- 

 tion of the stamens and pistil, sometimes by their not coming to 

 maturity at the same time. Under these circumstances the trans- 

 ference of the pollen from the stamens to the pistil is effected 

 in various ways. In some species the pollen is carried by the 

 action of the wind ; in- some few cases, by birds ; but in the 

 majority, this important object is secured by the visits of insects, 

 and the whole organization of such flowers is adapted to this 

 purpose." 



Parasitic Insects (Ichneumons and Tachinoc). — While insec- 

 tivorous birds accomplish much towards reducing the numbers 

 of injurious insects, they often as likely as not eat the beneficial 



