DIPTERA.— SCENOPINIDE. 553 
it forms a conical muzzle; the tongue is short and acute, but the 
maxilla and mandibles are wanting (fig. 130. 10. mouth of Doli- 
chopus)* ; the abdomen is compressed and incurved at the tip, with 
the male organs of generation often exserted in the shape of flattened 
sete or plates; the legs are long and slender, armed with strong 
bristles. In several important characteristics, these insects approxi- 
mate to the Athericera, and recede considerably from the type of the 
Tanystoma. 
Some of these insects are found running with great agility forwards, 
sideways, and backwards, upon walls, trunks of trees, &c., in damp 
situations; others delight in frequenting the wet edges of water, 
flying over its surface, and resting upon any thing which may happen 
to be floating upon it. It is seldom that they are found upon flowers. 
The Medeteri and Hydrophori subsist upon other insects; and M. 
Macquart states that he once captured a species of the latter genus 
engaged in sucking the larva of a Tettigonia; Mr. Doubleday also ob- 
served Medeterus loripes engaged in capturing Podure on the surface 
of water (Hint. Mag. vol. iii. p. 414.). 
The larva of Dolichopus ungulatus (the only species of which the 
transformations have been observed), according to De Geer (Meém. 
tom. vi. pl. 11. fig. 19.), resides in the earth ; it is apod, cylindrical, 
12-jointed (fig. 130. 12.), with a head of variable shape, furnished 
with two hooks; the last segment is incrassated, and reflexed and 
bicuspidate at the tip, with two tubercles above, each bearing a 
spiracle; the pupa (fig. 18. and my fig. 130. 13.) is naked, incom- 
plete, elongate-ovate; the thorax with two curved horns; and the 
segments of the abdomen are dorsally furnished with rows of bristles. 
The British genus Diaphorus, having the eyes in the males nearly 
extending over the entire surface of the head, appears to connect this 
family with the Scenopinide, 
The family Scenorinip® (fig. 130. 14. Scenopinus fenestralis), in 
which, after Latreille, I have united Meigen’s families Platypezine, 
Megacephali, and Scenopinii, or the tribes Scenopiniens, Cephalop- 
sides, and Platypezines of Macquart, is of small extent, and composed 
of insects of small size, obscure colours, and difficult location. In the 
* Mr. Haliday describes them as present in Macherium and Porphyrops. 
