ARMATURE OF PUP^E 



and tipularian Diptera, the appendages, wings, and compound eyes 

 being substantially those of the iinago. " With the exception of the 

 prothoracic respiratory appendages and the tail-fin, there is little in 

 the pupa of Chironomus which does not relate to the next stage." 



The exact homology of the " glazed eye " of the lepidopterous 

 pupae and of the parts under the head, situated over the maxillae, is 

 difficult to decide upon, and these points need farther examination. 

 In the dipterous pupa it is interesting to observe that the halteres 

 are large and broad, which plainly indicates that they are modified 



Fio. 583. Simulium piscicidium : a, larva; b, c, d, pupa; e, thoracic leg;/, row of bristles 

 at end of body. A, S. pecuarum, pupa ; a, b, c, adruinicula. After Eiley. 



hind wings. The number and arrangement of the spiracles is differ- 

 ent in pupae from those of the larva and imago. 



There are also secondary adaptive structures peculiar to the pupa, 

 which are present and only of use in this stage. These are the 

 thoracic, spiracular, or breathing appendages of the aquatic Diptera 

 (Fig. 583), the various spines situated on the head or thorax, or on 

 the sides, or more often at the end of the abdomen, besides also the 

 little spines arranged in more or less circular rows around the abdom- 

 inal segments, the cocoon-breaker, and the cremaster of many pupae. 



In the pupa of certain Diptera, there is a terminal c remaster-like 

 spine, as in that of Tipula eluta (Fig. 584), Tabanus lineola (Fig. 585), 

 besides adminicula or locomotive spines like those of lepidopterous 

 pupae (Fig. 580, a, 6, c). 



