162 Journal New York Entomological Society. [Vol. xxv. 



Fig. 5. Young larva of same species, in first molt. Drawn from life. 



Fig. 6. Egg of Chrysops callidus, a few hours after oviposition, showing 

 pigment developing symmetrically. 



Fig. 7. Larva of Chrysops callidus after first molt. Ventral side, show- 

 ing ventral and lateral prolegs. 



Fig. 8. Same larva (slightly more extended). Dorsal side, showing tra- 

 cheal trunks and Graber's organ. 



Plate XI. 



Figs. I and 2. Young larvae of Chrysops callidus and Tabamis atratiis, 

 to illustrate the difference in the tracheal system. 



Fig. 3. Head and first segment of young larva of Chrysops callidus, mag- 

 nified. Note the long terminal joint of the antennae. The first joint, which 

 is very short, was not noticed when the drawing was made. 



Fig. 4. Posterior end of newly-molted larva. Dorsal view. Graber's 

 organ, sk., shed skin, still adhering. 



Fig. s. Posterior end of newly-molted larva. Ventral view, showing 

 anus, stigmatal spine and bristles. 



Plate XII. 



Fig. I. Egg-mass of Chrysops spec, on underside of Nuphar leaf (turned 

 upside down). Lateral view. 



Fig. 2. Same egg-mass seen from above. 



Figs. 3, 4 and 5. Dorsal, lateral and ventral view of two-day-old egg of 

 Chrysops spec. Note the empty space above the embryo. 



Fig. 6. Egg and embryo of the same species, three days old. The eyes 

 have appeared. The yolk is diminished in quantity. 



Fig. 7. Egg with embryo of same species, four days old. 



Fig. 8. Egg from same egg-cluster, four days old, but developed a little 

 farther. Body segments and Graber's organ developed. 



Fig. 9. Newly-hatched larva of Chrysops spec. Head retracted and pro- 

 legs not yet exserted. 



Fig. 10. Graber's organ and posterior part of dorsal vessel of same larva, 

 magnified. 



Figs. II and 12. Movements of the posterior part of the body of the larva 

 before hatching. 



Literature on Early Stages of Chrysops. 



Zetterstedt. Diptera Scandinavise, I., p. 123. 



1882. Beling, Th. Beitrag zur Metamorphose zweifluegeliger Insekten. 

 Archiv fuer Naturgeschichte, 48. Jahrg., 1-2, pp. 187—240. 



1895. Hart, Charles A. On the Entomology of the Illinois River and Adja- 

 cent Waters. Bulletin of the Illinois State Laboratory of Natural 

 History, V., 4, pp. 220—247. 



