HOW TO KNOW THE IMMATURE INSECTS 



13b. Proximal tarsal segments of pro thoracic legs not dilated nor do 

 they differ greatly from the same segments of the other legs; 

 forcep-like structures occur at caudal end of abdomen. 

 Fig. 64 Order DERMAPTERA 



About 1,000 species of earwigs are known. 

 They are probably omnivorous but seem to pre- 

 fer animal food. When alarmed or molested, 

 the extremity of the abdomen is often upraised 

 and the forceps widely opened in a threating 

 manner. The eggs are deposited in the soil in 

 a group and the female rests over them. The 

 nymphs resemble their parents except the for- 

 ceps are simple and more or less styliform. 

 They pass 4 to 6 molts before reaching the adult 

 stage. 

 Fig. 64. Forficula sp. 

 14a. Mouth parts external, visible and in form of a trough-like tube or 

 a cone; wing rudiments usually visible. Fig. 65 15 



14b. Mouth parts intemaL short piercing 

 stylets withdrawn into head parallel 

 with meson, with no external labium; 

 wing rudiments absent; tarsi scon- 

 sorial type. 

 Fig. 66 Order ANOPLURA 



SECTIOH TU8£ 

 NIOUTH OPEWiA/* 

 neSTOMAL 

 TetTH 



Fi^. 66. Hog louse, Hoematopinus odvan- 



ticius Neum. (U.S.D.A.); b, its mouth 



Fig. 65. Head of thrips. 



The sucking lice ore blood- 

 sucking ectoparasites o f 

 mammals and around 500 

 species have been describ- 

 ed. Of these, two species in- 

 fest man and about a dozen 

 occur on domestic animals. 

 The louse lays up to 300 

 eggs, which are usually at- 

 tached to a hair or fibre. 

 The egg period is about a 

 week. Three moults occur 

 during the life and the young 

 resemble the adult in exter- 

 nal features. 



37 



