Not much flattened laterally or over one-quarter of an inch in length 64. 



64. Minute, soft and whitish; found in old books and papers 



CorrodenUa Book-lice 

 Not so 65. 



65. Body much flattened dorso-ventrally 66. 

 Body more circular in cross section 70. 



66. With large structures resembling a pair of pinchers on the posterior end 



of the body 



Dermaptera Earwigs 

 Not so 67. 



67. Antennae long, from one-third to equal to the length of the body; with 



two or three, long, jointed, tail-like processes on the posterior end; not 

 parasitic on animals 



Thysanura Silver-fish or Bristle-tails 

 Antennae very short; no long, jointed, caudal appendages; parasitic on 

 birds or mammals 68. 



68. With biting mouth parts; parasitic mostly on birds, a few species on 



mammals 



Mallophaga Bird Lice or Biting Lice 

 With sucking mouth parts; on mammals 69. 



69. Tarsus (last section of foot) with three segments, and ending in two 



hooks 



Heteroptera, Cmiicjdae Bedbugs 

 (Hemiptera (part) ) 

 Tarsus with one segment and ending in a single hook which opposes a 

 projection from the tibia or section above 

 Siphunculata True Lice 

 (Anoplura) 



70. Parasitic on birds and mammals; antennae short 7L 

 Not parasitic on animals; antennae long or short 72. 



71. With biting mouth parts; common on birds, occasional on mammals 



Mallophaga Bird Lice or Biting Lice 

 With sucking mouth parts; common on mammals 

 Siphunculata True Lice 

 (Anoplura) 



72. Body thickly coated with small scales or hairs 73. 

 No thick coat of scales or hairs 74. 



73. Very small; usually found in groups; with beak-like sucking mouth parts 



Homoptera, Aphuiidae Woolly Aphids 

 Usually about ^2" long; rarely in groups; mouth parts not evident 

 Lepidoptera, Lxpandae and Geometndae (part) 



Female Tussock-moth, Female Canker-worm Moths 



74. With a pair of prominent, pincher-like mouth parts as long as, or longer 



than, the head 



J^leuroptera Ant-lion, Aphis-lion 

 Not so 75. 



239 



