PLATE I. — To Illustrate the Anatomy of the Larva. 



Fig. 1. — Full-grown larva of Culcx annulalus (Schrank) : a, respiratory 

 syphon ; 6, swimming fan ; c c c c, anal papillae. 



Fig. 2. — An antenna, more magnified. 



Fig. 3. — Respiratory syphon more enlarged, to show : n, the muscles ; b, the 

 valve-like terminal lobes ; c, the stigma. 



Fig. 4. — Segmental respiratory apparatus : a, part of the main longitudinal 

 trunk ; h, lateral branch ; c, cord by which tlie cast-off lining of the 

 tubes is withdrawn during ecdysis. 



Fig. 5. — Left mandible, seen from below. 



Fig. 6. — Right maxilla, seen from below: a, internal lobe ; b, external lobe ; 

 c, maxillary palp. 



Fig. 7. — Labium, with the lower part of the pharynx, seen from above: 

 a, the labrum itself. 



Fig. 8. — One of the natatory compound bristles, much magnified. 



Fig. 9. — Thorax of larva of C. pipiens, to show : h, the hepatic masses ; 

 i, intestine ; t, main longitudinal tracheae. 



It will be noticed that in this species the thoracic dilatations of the main 

 tracheae are by no means so marked as in C. annulatus (Schrank), and 

 the whole respiratory system is less developed. 



This plate is partly based on Meinert's figures, and partly original. 



