114 OHIO BIOLOGICAL SI'RVEY 



EXPLANATION OF PLATE ViL 



Figures 142-144 inclusive, Eristalis tenax (Linne) ; all 

 the others from Eristalis aeneiis (Fabricius), 



Fig. 131 Dorsal view of mature larva X 9; a, antennae; b, anterior larval respiratory 



cornua; c, the large tiaclieal trunks; d, the posterior respiratory tube or 



"rat-tail."' To avoid confusion the vestiture is not represented in this figure. 

 P"ig. 132 The anterior larval respiratory cornua, much enlarged, dissected out to show 



the large trachea leading from it. 

 Fig. 133 Distal end of respiratory tube highly magnified showing wrinkling on out- 

 side, the two inner trachea (a) the spiracles at the tip (b) and the delicate 



feather-like (interspiracular?) appendages (c). 

 Fig. 134 A small area of ihe basal segment of the tube much enlarged, showing the 



nature of the vestiture and wrinkling. 

 Fig. 135 A small area of the median segment of the tube much enlarged to show the 



nature of the vestiture and wrinkling. 



A, one of the bifid (segmental ? ) hairs of the larva, and b, one of the integ- 



umental hairs of the body, drawn to the same scale as Figs. 134 and 135. 



The anal opening of the larva (a) with the retractile flabellae (b) much en- 

 larged. 



Ventral view of the head of the larva much enlarged; a, antennae; b. mouth 



hood; c, the first pair of pro-legs. 



Mouth-hood and esophageal framework of larva dissected out and much 



enlarged. 



The chitinized parts of the esophageal framework from the side; a. mouth- 



hooklets?; b, outer pair of mouth-hooks? 



The same from the ventral view. 



Three eggs from an egg-mass of E . tenax, x 17. 



A small area of the egg-shell to show sculpturing; highly magnified. 



Lateral view of larva of E. tenax, two hours after hatching, x 17; a 



antennae; b, pro-legs; c, trachea; d, posterior respiratory appendage. 

 Fig. 145 Lateral view of puparium of E. aeneus x 4; a, anterior larval respiratory 



cornua; b, pupal respiratory cornua; c. posterior respiratory appendage 



("rattail"); d, position of anus; e, pro-legs of larva. 

 Fig. 146 Nymph dissected out from puparium x 3; a, the pupal respiratory cornua, 



with their internal connections to the prothoracic spiracle of the adult; b, 



knee of front leg; c, wing-pad; d, scutellum. 

 Fig. 147 Pupal respiratory cornua much enlarged showing the numerous tubercles. 

 Fig. 148 Two tubercles of pupal respiratory cornua, highly magnified, showing their 



radiating elevations (spiracles?). 



