THE LEAP BEETLES. 



1097 



more or less highly colored. Some of them are flattened and curi- 

 ously armed with spines, while others are partially covered with 

 their own excrement. A few are leaf miners or stem borers, and 

 these are long and slender and without the conspicuous markings of 

 those which feed in the open. The larvae of one large group (Gamp- 

 tosoma) are case-bearers ; others, including an entire tribe (Eumol- 

 pini) are root-feeders. When ready to transform, many of the leaf- 

 eating larvae fasten themselves by the tail or last abdominal segment 

 to a leaf and enter the chrysalis stage, while others go into the 

 ground when about to change to a pupa. The case-bearers pupate 

 within the sealed-up larval case. 



About 18,000 species of Chrysomelida? are known, 750 of which 

 are from North America. These are arranged in twelve tribes, all of 

 which are represented in Indiana. The literature pertaining to the 

 different tribes is widely scattered, and the more important papers 

 will be noted under the respective tribal headings. Two which at- 

 tempt to treat of the United States or Canadian species of the fam- 

 ily as a whole are as follows : 



Crotch, G. E.— 1 'Materials for the Study of the Phytophaga of 



the United States/' in Proc. Phil. Acad. Nat. Sci., 1873, 



19-83. 



Wickham, E. F. — "The Chrysomelidae of Ontario and Quebec," 

 in Can. Ent, XXVIII, 1896 ; XXIX, 1897. 



The different forms of tarsal claws are much used in the classifi- 

 cation of genera, and the beginner is urged to familiarize himself 

 with these as described on page 18. 



KEY TO TEIBES OF CHRYSOMELIDiE. 



a. Head produced, constricted or neck-like behind the eyes ; thorax much 

 narrower than elytra and without lateral margins (raised edges) ; 

 mandibles simple* pointed (Eupocla). 

 h. First ventral segment about as long as all the others united; form 

 elongate ; prosternum very narrow ; tarsal claws simple, divergent. 



Tribe I. Donactixi, p. 1098. 

 &&. First ventral about as long as or somewhat shorter than the two fol- 

 lowing. 



c. Elytral punctures irregular; tarsal claws cleft or toothed; pro- 

 sternum distinct. Tribe II. Sagktnl p. 1107. 

 cc. Elytral punctures in rows; tarsal claws simple, divergent; pro- 

 sternum very narrow. Tribe III. Criocerixi, p. 1110. 

 da. Head inserted in the thorax to the eyes; thorax as broad, or but little 

 narrower, than elytra, usually margined on the sides; mandibles with 

 several teeth. 



cl. Thorax and elytra without broad, expanded margins; head usually 

 plainly visible from above. 



