EXPLANATION OF PLATE XI. 



Euratas formidabilis , Distant. 



Fig. i. — First larval instar, from a specimen preserved in alcohol. 

 ,, 2. — Second larval instar, from a specimen preserved in alcohol. 

 ,, 3. — Third larval instar (= Fabatus servus, Distant) from a fresh specimen. 

 ,, 4. — Head and pronotum of third larval instar, from a specimen immersed in 



alcohol for twenty-four hours and then dried (more highly magnified 



than fig. 3). 

 ,, 5. — Male genitalia as seen from below, from a preparation mounted in Canada 



balsam : x 20. 



The dorsal sclerite of the ninth segment has been thrust to one side and its lateral 

 angles are somewhat folded inwards in order to show the group of spines near the margin 

 on the dorsal surface. 



,, 6. — Female genitalia as seen from above in a retracted condition after removal 

 of the 8th dorsal sclerite, from a specimen mounted in Canada bal- 

 sam : x 30. 



a. Genital aperture. e. Ovipositor. 



b. Genital hood. /. Posterior appendage. 



c. Anterior appendage. g. 10th abdominal segment. 



d. Inner branch of anterior appendage. h. Anal segment. 



,, 7. — Female genitalia, lateral view in extended condition, slightly diagram- 

 matic : X 30. 

 Lettering as in preceding figure. 



Eristalis arvorum, Fabricius. 



Fig. 8. — Ventral view of larva with tail partly retracted. 

 ,, 9. — Lateral view of anterior extremity of larva, viewed as a transparent 

 object : x 8. 



a. Sensory papilla. d. Pharynx. 



b. Anterior extremity of the lateral tra- e. Chitinous skeleton of pharynx. 



cheal trunk. /. Antechamber of pharynx. 



c. First foot. 



Palpomyia sp. 

 Fig. 10. — Dorsal and ventral views of cast pupal skin. 



