METAMORPHOSIS OF BARK LICE 



627 



as are the wing-pads ; the front pair of legs are extended forward. " If dis- 

 turbed, they twist and bend their bodies quite vigorously." The pupa state lasts 

 two or three weeks. A similar pupa is that of leery a 

 rosce. (Itili'v and Howard.) 



The metamorphosis of A*/>i<lii>titx jn-r/ni-ingits is of 

 interest. The male nymph differs much after the first 



a 



d 



FIG. 580. Pupa obteeta of Diptera : a, Ptychoptera ; 6, TnJianitB 

 ; c, Proctacanlhus philadelphieug ; d, Midas elavatus. 



Fio.581. Pupa libera 

 ofleeryit jim-c/mxl, \en- 

 tral view. After RUey, 

 Insect Life. 



moult from the female, having large purple eyes, while the female nymph 

 loses its eyes entirely. It passes into what Kiley terms the pro-pupa (Fig. 582, 

 i>), in which the wing-pads are present, while the limbs are short and thick. 

 The next stage is the -'true pupa" (Fig. 582, c, cZ), in which the antenme and 

 legs are much longer than before. There is no waxy cocoon, but only a case 



FIG. .iS2. AKjiiilintiix iii-r>i!<-!<intix, development of male insect : a, ventral view of larva after 

 tir-t moult; 1>, the same, after >eeon<l moult (pro-pupa >t:ii:vt; c and <l, true pupa, ventral and 

 dorsal views. All (.'really enlarged. After Uilev. 



or scale composed of the shed larval skin, i.e.. "with the first moult the shed 

 larval skin is retained beneath the scale, as in the case of the female ; with the 

 later moultings the shod skins are pushed out from beneath the scale," and when 

 they transform into the imago they "back out from the rear end of their 

 scale." 



