316 DIPTERA. 
rous claws. These are the general cha- 
racters of the genus ; now I will give 
you those which distinguish the species. 
Lucy, But first, mamma, what does 
bivalve mean ? 
Mother, Bivalve is composed of two 
valves, or shutters, which close together : 
thus an oyster, a cockle, and a muscle, 
are said to have bivalve shells, that is, 
the two parts, of which the shell consists, 
are jointed to one another, and shut close 
together. 
Lucy, Thank you, mamma, I under- 
stand that very well; now will you ex- 
plain obtuse ? 
Mother, Obtuse means blunt, in op- 
position to an acute or sharp angle. The 
first species, the H, equina^, broad, flat, 
and scaly — head yellow — eyes brown — 
thorax and abdomen yellowish, with 
brown waves — wings obtuse, cross each 
other, a brown spot near the margin, and 
* From Equus, a horse. 
