86 
Place nymphae in drops of water on a slide and 
examine the air syphons. They appear to be of special 
value in the differentiation of genera. 
1. Ano'phelinae .—The syphons have a square 
truncated end, and are proportionately much shorter 
than in Culex , and project from about the middle of 
the thorax (Figs. 30 and 31). 
2. Culex. —The syphons are long and narrow, 
and have an oblique opening, and project from the 
posterior portion of the thorax (Figs. 30 and 31). 
3. Stegomyia and Desvoidea. —The syphons are 
broadly triangular, and are characteristic. Note the 
marked contrast in appearance to those of Culex 
(Fig. 32). _ 
Fig. 32 . Nymphal Syphon Tube of Stegomyia 
4. Corethra and Mochlonyx. — (a) Note in Corethra 
the pointed syphons with slit-like opening and the 
straight tail (Figs. 31 and 33). 
( b) Note in Mochlonyx the Culex-Yike nymph and 
the thin rounded and pointed syphons with circular 
opening (Fig. 31). 
5. Chironomus. —Examine the bottoms of pools 
of polluted water, and note in the mud the brilliant red 
nymphs and larvae of Chironomus (Fig. 33). 
1. Note that the nymph has a large globular 
body (head and thorax) and bears a general resemblance 
to mosquito nymphs. 
