44 THE STUDY OF INSECTS 



RR. Front tarsi not enlarged. 



S. Minute insects, less than J of an inch in 

 length; antenna,' nine-jointed, p. 62 



ZoRAPTERA 



SS. Larger insects; antenna: usually more 

 than nine-jointed. (White-ants), p. 63 



ISOPTERA 



00. Cerci absent; antennas usually with eleven 



joints, p. 127 COLEOPTERA 



HH. Antenna? short, not pronounced; larval forms. 



I. Body cylindrical, caterpillar-like. p. 178 Mecoptera 



II. Body not caterpillar-like. 



J. Mandibles sickle-shaped; each mandible with a furrow over 

 which the maxilla of that side fits, the two forming an organ 

 for piercing and sucking. (Ant-lions, aphislions, hemero- 



biids). p. 66 Neuroptera 



JJ. Mouth-parts not of the ant-lion type. 



K. Larva of Raphidia. p. 66 Neuroptera 



KK. Larvae of beetles, p. 127 Coleoptera 



EEE. Mouth-parts haustellate, fitted for sucking; mandibles not sickle- 

 shaped. 

 F. Body covered with a waxy powder or with tufts or plates of wax. 



(Mealy-bugs, Orthezia). p. 94 Hemiptera 



FF. Body more or less covered with minute scales, or with thick long 

 hairs; proboscis if present coiled beneath the head. (Moths), p. 183 



Lepidoptera 



FFF. Body naked, or with isolated or bristle-like hairs. 



G. Prothorax not well developed, inconspicuous or invisible from 



above, p. 286 Diptera 



GG. Prothorax well developed. 



H. Last joint of tarsi bladder-like or hoof-like in form and usually 

 without claws; mouth-parts forming a triangular un jointed 



beak. p. 89 Thysanoptera 



HH. Last joint of tarsi not bladder-like, and furnished with one 

 or two claws; mouth-parts forming a slender, usually jointed 

 beak. 



I. Beak arising from the front part of the head. p. 94. Hemiptera 



II. Beak arising from the back part of the head. p. 109. Homoptera 

 BB. Either without a distinct head, or without jointed legs, or incapable of loco- 

 motion. 



C. Forms that are legless but capable of locomotion; in some the head is dis- 

 tinct, in others not. Here belong many larvas representing several of the 

 orders, and the active pupas of mosquitoes and certain midges. It is im- 

 practicable to separate them in this key. 

 CC. Sedentary forms, incapable of locomotion. 



D. Small abnormal insects in which the body is either scale-like or gall-like in 



form, or grub-like clothed with wax. The waxy covering may be in the 



form of powder, or large tufts or plates, or a continuous layer, or of 



a thin scale, beneath which the insect lives. (Coccidae). p. 94 Hemiptera 



DD. Pupae, the inactive stage of insects with a complete metamorphosis; 



capable only of a wriggling motion, and incapable of feeding. 



E. Obtected pupae, pupas in which the legs and wings are glued to the 



surface of the body; either in a cocoon or naked, p. 183. . . .Lepidoptera 



EE. Coarctate pupas, pupae enclosed in the hardened larval skin. p. 286 



Diptera 



EEE. Exarate pupae, pupas that have the legs and wings free; either in a 

 cocoon or naked. This type of pupa is characteristic of all of the orders 

 in which the metamorphosis is complete except the Lepidoptera and 

 Diptera. 



