CLASSIFICATION OF INSECTS. 6l 



BB. With four wings. 



C. The two pairs of wings unlike in structure. 



D. Front wings leathery at base, and membranous at tip, often 

 overlapping. Mouth-parts formed for sucking. Page 75. 



Hemiptera. 

 DD. Front wings of same texture throughout. 



E. Front wings horny or leathery, being veinless wing covers. 

 {Elytra.) 



F. Abdomen with caudal appendages in form of movable for- 

 ceps. Page 69 EUPLEXOPTERA. 



FF. Abdomen without forceplike appendages. Page 85. 



COLEOPTERA. 

 EE. Front wings leathery or parchmentlike, with a network of 

 veins. 



F. Under wings not folded. Mouth-parts formed for suck- 

 ing. Page 75 Hemiptera. 



FF. Under wings folded lengthwise. Mouth-parts formed 



for biting. Page 70. Orthoptera. 



CC. The two pairs of wings similar, membranous. 



D. Last joint of tarsi bladderlike or hooflike at the tip. Page 74. 



Physopoda. 

 DD. Last joint of tarsi not bladderlike. 



E. Wings entirely or for the greater part clothed with scales. 



Mouth-parts formed for sucking. Page 80 Lepidoptera. 



EE. Wings naked, transparent, or thinly clothed with hairs. 

 F. Mouth-parts arising from the hinder part of the lower 

 surface of the head, and consisting of bristlelike organs in- 

 closed in a jointed sheath. {Homoptera.) Page 75. 



Hemiptera. 

 FF. Mouth-parts in normal position. Mandibles not bristle- 

 like. 



G. Wings net-veined, with many veins and cross-veins. 

 H. Tarsi consisting of less than five segments. 



I. Antennae inconspicuous, awl-shaped, short, and slen- 

 der. 



J. First and second pairs of wings nearly the same 

 length ; tarsi three-jointed. Page 65. . .Odonata. 



JJ. Second pair of wings either small or wanting ; 

 tarsi four-jointed. Page 64 Ephemerida. 



II. Antennae usually conspicuous, setiform, filiform 

 clavate, capitate, or pectinate. 



