40 



BIRDS IX THEIR RELATIONS TO MAX. 



AX APHID, MAGNII-M- 



third generation. All of these early broods are what are 

 called parthenogenetic females, giving birth to living young 

 without the presence of any males. Many of these plant-lice 

 are provided with wings, but the majority are wingless. This 

 process of reproduction is continued throughout, the warm 



season, but on the ap- 

 proach of cold weather 

 a true sexual genera- 

 tion is produced, the 

 males of which may be 

 either winged or wing- 

 less, while the females 

 are always wingless. 

 By union of these two 

 forms the true winter 

 eggs are produced : the 

 eggs are generally deposited upon the branches of trees or 

 other plants; they pass through the winter and in spring- 

 hatch into stem-mothers which renew Hie cycle of existence. 

 Many of the smaller birds, such as the warblers, nut- 

 hatches, kinglets, and chickadees, appear to feed largely upon 

 aphides and their eggs. These insects are only rarely found 

 in the stomachs of larger birds, lik the robin, cat-bird, and 

 the various thrushes. A large part of the winter food of the 

 chickadee consists of the eggs of aphides. 



The moths and butterflies form the order Lepidoptera, or 

 scaly-winged insects. Under the microscope their wings are 

 shown to be covered with minute scales which overlap- one 

 another. The adults are very different from the larvae, and 

 in consequence these insects are said to undergo complete 

 transformations. The three later stages of the common cat- 

 erpillar which infests cabbages the cabbage-worm are rep- 

 resented in the picture herewith. The female butterflies 

 deposit their pale greenish-yellow eggs, singly or in clusters, 

 on the leaves ; the larvaj soon hatch and feed upon the sur- 



