THE A CAR IN A OR MITES— BANKS. 



53 



the male of one .species there is a hole in the jaw, through which the 



bubble is blown, part hanging down on either side. 

 Trouessart has shown that in RaUlietia there is a true parthenogen- 

 esis; agamic generations are found 

 in spring and summer, the male ap- 

 pearing only in the autumn or winter. 

 He also found that this form has no 

 m-niph, the larva changing into the 

 adult female. 



Gamasids deposit eggs which 

 hatch into pale, soft-skinned, six- 

 legged larvie, often very different 



Fig. 92.— Liponyssus a.mericanus. 



Fig. 93.— LiPONYssrs; anal plate 



AND MANDIBLE. 



from the adult. There is a remarkable exception in Ptei'optus and 

 allied genera of the Derman3'ssidffi; the young of these mites hatch 

 with eight legs. In time the larva molts into an eight-legged nymph. 



Fig. 94.— Pneumonyssvs .'^imicola, 

 from below. 



-Larva hf pnei'monyssus 

 simicola. 



In thi.s stage they have shield.^, the dorsal often transversely divided. 

 The nymphal stage is often the longest and most active period of their 



