THE HIDDEN TYPE OF WING-GROWTH 127 



forms a compact rigid region for the attachment of the strong 

 wing-muscles. The tip of the labium forms a complex sucker, 

 while mandibles and maxillae may be developed as piercers. 

 As our first example from this order, we may take the grub 

 of one of the black-flies (Bibio) ; the stages of B. johannis 



FIG. 72. 



A, Larva (dorsal view) of Blackfly (Bibio johannis) ; sp, spiracles, x 8. 



B, mandible, and C, maxilla of larva (p, palp ; I, lobe), xgo. D, terminal 

 segments (n and 12) of body (sp, spiracles), x 20. E, pupa (ventral 

 view) ; an, feeler ; w, wing ; l lt 1 3 , fore- and hind-legs, x 8. After 

 Morris, Ann. Appl. Biol. IV. 



have been described rather fully. 1 When hatched this larva 

 is about 1.5 mm. long (/o inch) with a firm rotund head and a 

 body of twelve segments which bear long, slender bristles in 



1 H. M. Morris : " On the Larval and Pupal Stages of Bibio johannis, 

 L. ". Ann. Appl. Biol., IV. 1917. 



