34 



The Larva of Chironomiis 



local develoiDinents of sucli rings. They vary much in 

 luimber and position ; three or four may be borne upon 

 the same segment instead of the usual pair ; and such 

 facts point to their secondary, adaptive character. On 

 the other hand, their usual segmental arrangement, and 

 the normal occurrence of generally similar parts in 

 insect-embryos, in the larvae of several different orders of 

 insects, especially Lepidoptera and Hymenoptera (Saw- 

 Hies), in adult Myriopods and Peripatus, tend to support 



the view that they are 

 true appendages, homolo- 

 gous with the thoracic 

 legs of many insects. 



Chironomidae often, but 

 not always, exhibit such 

 an arrangement of pseu- 

 dopods as we have de- 

 scribed in the Chirono- 

 mus-larva. The larva of 

 Ceratopogon is footless. 

 One of us found some 

 years ago in a stream 

 near London a Dipterous 

 larva v/ith remarkable 

 pseudopods (fig. 22). This 

 has since been redis- 

 covered and identified. 

 The head was very small 

 and retractile. The 

 stomach was filled with 

 a red fluid, as if the 

 larva had been feeding 

 upon Tubifex. The body, 

 which was a quarter of 

 an inch long, apparently 

 consisted of a head and eleven segments ; eight seg- 

 ments (4-1 1 ) were provided with hooked ventral appen- 

 dages, most of which were minute, but the last pair were 

 comparable in size to the anal feet of the Chironomus- 

 larva. From the dorsal surface of the last segment pro- 

 jected three small, cylindrical processes, each of which 

 bore four filaments, and resembled the sensory pro- 

 cesses of Chironomus ^ or Tanypus. No prothoracic 



Fig. 22. — Larva 01 Clinoccra showing 

 pseudopods on eight segments, i, dorsal 

 view. 2, side view. X 20. 



See pp. 35, 49. 



