THE BEETLES 



153 



II. BEETLES WITH FOUR-JOINTED TARSI (TETRAMERA) 



The tarsi of the families of this section are apparently composed 

 of but four segments, the fourth being very small and closely joined 



to the last, or fifth, segment, and concealed by 

 the third segment, which is deeply bilobed. This 

 section is often called the Pkytophaga, as all of 

 the families attack vegetation. 



The leaf-beetles (Chrysomelidae) are one of the 

 largest and most injurious families, there being 

 some six hundred species in this country, a large 

 number of which injure cultivated crops, while 

 those which normally feed on various weeds often 

 change their food habits and become crop pests. 

 The Colorado potato-beetle (Leptinotarsa decem- 

 FIG. 219. Tarsus liticiita) is one of the best-known species, and is 

 of phytophagous fairly typical of the family, except that it is much 



Msdnct'^ourth lar S er than the avera g e - The little black > red-and- 

 segment yellow-spotted asparagus-beetles which, with their 



(After Comstock, dark grayish, sluglike larvae, eat into young aspar- 

 agus, are well known throughout the East, as are 

 the twelve-spotted asparagus-beetles, which are red with twelve 

 black spots. 



FIG. 220. The common asparagus-beetle, eggs, larva, and adult. (Much enlarged) 



(After Britton) 



