53 



CHIRONOMUS 16. 



LARVA: length 3 mm.; green; segments i, 2 and 3 swollen; head pointed; pointed 

 submentum bearing twisted hairs ; trachea; complete ; tracheal gills double 

 usual length, constricted in the middle ; sides of the body fringed with many 

 single and tufted hairs, all short. 



LARVAL DWELLING : free. 



HABITAT : rivers and streams. 



CHIRONOMUS 17. 

 LARVA : length 8 mm. ; pale green ; head short, as wide as body ; very small brain 



within the head ; tracheae complete ; tracheal gills ; single long hair from 



segments 5-10 laterally ; anal set;e 6. 

 LARVAL DWELLING : mass of conferv;e moored to stone. 

 HABITAT : clear running brooks and rivers. 



CHIRONOMUS 18. 

 LARVA : length 10 mm. ; quite transparent ; long antennae with large transparent bulbs, 



one on each side of antenna, unsymmetrically placed ; fat-sacs small but 



easily seen in segment 10 ; body hairless. 

 LARVAL DWELLING : mud tube, winding, with transparent silk web over it and extending 



beyond it. 

 HABITAT : in bed of rivers and streams. 



CHIRONOMUS 19. 



LARVA : 8 mm. ; brown ; complete stout tracheas. 

 LARVAL DWELLING : tube 1-2 cm. long, attached most of its length to stem of moss, 



composed of transversely placed fibres and sticks, after the manner of the 



case of Limnophihis rhombicus (Trichoptera.). 



P.S. All these larvae possess the usual two pairs of anal gills. The tracheae of 

 all larvae possessing them are closed, there are no open spiracles, but initial threads 

 may often be seen. 



