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articulate with the pharyngeal skeleton, which is formed by two 
lateral plates, connected with a ventral bar; the plates are ante- 
riorly narrow and become broader posteriorly; at the end they are 
deeply incised. The larva is metapneustic and the posterior spi- 
racles are situated in the hind margin of the anal segment; the 
atrium is long, somewhat clavate and ending with two knobs. 
Figs. 10—14. Spiracles of the larva af Mydæa anomala. Fig. 10. 1' stage. 
posterior RS Figs. 11—12. 2' stage. anterior and posterior spiracles. 
Figs. 13—14. 3' stage. anterior and posterior spiracles. 
Second stage: In this stage the spines are less numerous; 
the segments 2—4 have spines only on the anterior border but 
on the following segments also the posterior margins are provided 
with spines and the 12th segment bears spines on the whole sur- 
face. The direction of the spines is the same as in the first stage. 
