COKSTITTJENTS OF FOOD. 



9 



Fig. 3.— Leaf -beetle {Systena 

 hlanda) (after Chittenden; 

 loaned by Division of Ento- 

 mology). 



and Acridid^ — see fig. 2). Coleoptera form a most important ele- 

 ment of bird food, the families of this order most largely represented 

 being the Scaraba3id8e or scarabseid beetles, the Carabidfe or ground- 

 beetles, the Elateridse or click-beetles, the Chrysomelidse or leaf- 

 beetles, and the Rhynchophora or weevils. Some of the scarabseids 

 that are eaten are the clumsy brown May-beetles and their allies, 

 which feed on growing plants ; others comprise 

 a group of beetles commonly known as dung- 

 beetles, because they subsist on the droppings 

 of animals. Ground-beetles are alert, active 

 insects, carnivorous in food habits. Click- 

 beetles are narrow and hard-shelled; when dis- 

 turbed, they curl up and 'play possum' until 

 the danger appears to be past, when they spring 

 into the air by spasmodically straightening out 

 their bodies with a sharp clicking sound. Their 

 larvae, wireworms, are often very destructive 

 to crops. The leaf -beetles (see fig. 3) taken by 

 birds are pests of little economic importance. 

 Weevils (see fig. 4) constitute a destructive class 

 of insect pests, and are extensively prej^ed on. Diptera furnish no sig- 

 nificant part of the food of birds, though the slow-moving crane-flies 

 (Tipulid?e) and midges (Chironomidse) are at times snapped up, and 

 some larval Diptera are occasionally eaten. The Hemiptera include 

 both leaf -hoppers (Jassidse), which derive their sustenance by probing 

 plants with their sucking beaks, and true bugs, which are flat, bad- 

 smelling insects. Some of the bugs feed like 

 leaf -hoppers on the juices of plants, while 

 others are predatory and subsist on succulent 

 insects. The hymenopterous element of bird 

 food is composed of ants, wasps, and a few 

 small bees, the wasps including flower-fertiliz- 

 ing species and parasitic species of the families 

 Ichneumonidse (see fig. 5), Braconidse, and 

 Scoliidse. 



The value of a bird as an insect destroj^er 

 depends upon the value of the insects it con- 

 sumes. Each insect eaten by birds must of 

 necessity be injurious, beneficial, or neutral in its effect on crops, 

 though it is not always easy to classify it properly. While present 

 information is sufficient to fix the status of some with sufficient accu- 

 racy for all practical purposes, in the case of others more light is 

 needed. The smaller- dung-feeding scarabseid beetles appear to have 

 little or no effect upon agriculture. The great majority of ants have 

 habits which are apparently of little interest to the agriculturist; 



Ftg. 4.— Weevil (after Chit- 

 tenden; loaned by Divi- 

 sion of Entomology). 



