506 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
The mouth parts of the adult are either suctorial or vestigial, in 
some species formed for piercing, in others for scraping. The larvae, 
usually referred to as maggots, are footless and vary greatly in form, 
some being slender and elongate, whereas others are stout and cylin- 
drical (fig. 128). The pupa may be free, loosely enclosed, or held 
immobile within the last larval skin, in which case it is called the 
puparium. <A few species enclose their pupae in cocoons. 
Ficure 128.—Various shapes of dipterous larvae (after different artists): A, 
Chrysopilus ornata; B, Rhagoletis pomonella; C, Mycetobia divergens; D, 
Hylemya cilicrura; EB, Culex restuans; F, Tabanus atratus; G, Hrinna lugen; 
H, Retinodisplosis inopis O. 8.3; 1, Leschenaultia exul; J, Musca domestica; K, 
Psilocephala frontalis. 
