332 INSECTA. 



cell of the wings is strongly unisinuate. Tlie body is generally 

 hairy. The antennae are closely approximated at base. 



Mallota, Meig. — Eristalis, Fab., 

 Where the last joint of the antennae forms a species of transvei-sal 

 trapezium, the widest side of which is before, and presenting, when 

 dilated an elliptical facet bordered all round *. 



Helophilus, Meig. — Eristalis, Meig., Fab., 

 Where the palette of the antennae forms a semi-oval. The body is 

 generally less hairy than in the preceding subgenera. 



The body of several of the larvae is terminated by a long tail, 

 whence their vulgar appellation of vers a queue de rat, or rat-tailed 

 worms. They elongate and raise it perpendicularly to the surface 

 of the water, or cloacae in which they live, in order to respire 

 through the aperture in its extremity. They are furnished internally 

 with two large and extremely brilliant trachae, which, near the origin 

 of the tail, form numerous plexus that are constantly in motion. 



Reservoirs of rain-water contain numbers of these larvae. Their 

 tail may easily be mistaken for filaments of roots. See Reaum., 

 Ins., IV, xxx. 



H.ienax; Musca tenax,L.; H. abeilliforme, Reaum., Ins., 

 IV, XX, 7. About the size of the male of the common Bee, and at 

 the first glance resembles it in colours. The body is brown, 

 covered with fine, yellowish-grey hairs, with a black streak on 

 the front ; from two to four fulvous-yellow spots on each side of 

 the abdomen. 



The larva inhabits muddy water, privies, and gutters, and is 

 one of those called vers a queue de rat. It is said to be so tena- 

 cious of life that no pressure can destroy it f . 

 Other Syrphidae diflfer from the last in the exterior and closed cell 

 of the posterior margin ; its external side being straight or but 

 slightly sinuous. The antennae are elevated at base and advance al- 

 most parallel with each other; their last joint is almost ovoid, or 

 nearly orbicular. The anterior projection of the head is very short. 

 The abdomen is generally narroAver and more elongated than in the 

 preceding subgenera. The wings, in those where it is shortest, are 

 generally distant. 



Syrphus, Lat, Meig. — Sc^va, Fab., 

 Or Syrphus, properly so called, where the abdomen is gradually nar- 

 rowed from base to point. 



* See Meigen. 



f The Helophili of Meigen, and most of his Eristales, those in which the seta of 

 the antennae is simple, such as the sepulchralis, ceneus, tenax, crypiarum, nemorum, 

 arbustorum, &c. 



We might pass from the Helophili to the Callicerae, Cerise, Chrysotoxa, Paragi, 

 Syrphi, terminate the division of those with a nasal prominence, by the Bacchae, and 

 begin the division of those in which that elevation is wanting, with the Asciae and 

 SpheginK, Insects closely allied to the Bacchre. Then would come Aphritis, Mero- 

 don &c. This series would, perhaps, be more natural. 



