ATTEMPTED DIVISION OF BRITISH INSECTS. 391 



Natural Order. — GEstrites, Bolts. 



Larva cylindrical, oblong; feeds in the stomachs, frontal cavities, 

 or backs of quadrupeds ; when full fed it falls to the ground. 

 Pupa changes in the earth, or, if the larva inhabit the stomach, 

 in the dung of the animal it has preyed on. Imago, with six- 

 jointed antennas ; basal and second joints short, scarcely distinct ; 

 third large, globose ; the remaining three forming a seta, which is 

 incrassated at the base ; organs of the mouth obsolete ; wings 

 divaricating ; alulae moderately large ; body pilose, short, stout. 

 Inhabits meadows and commons, flying about cattle, and causing 

 them much uneasiness ; this is done in order to deposit its eggs, 

 not for the purpose of attacking them : it takes no food. Qistrus, 

 Cuterehra. 



StIRPS. AsiLINA. 



Natural Order. — Leptites. 



Larva elongate, rather attenuated at the anterior end ; inhabits funnel- 

 shaped holes, which it constructs in loose sand, to serve as a 

 pitfall to small insects, on which it feeds ; the larva remains 

 perfectly motionless when waiting for its prey, and so nearly 

 resembles the surrounding soil in colour, that it is effectually 

 concealed from observation. Pupa changes in the same situation. 

 Imago, with antennae five-jointed ; the basal, second, and third 

 joints short, and somewhat globose, but varying much in the 

 genera ; the fourth and fifth closely united, and forming a long, 

 slender seta ; labium large, membranous, bilobed ; the maxillary 

 feelers long, two-jointed, and porrected ; ocelli three ; wings 

 long, divaricating, often spotted ; alulae obsolete ; body mode- 

 rately long. Inhabits moist hedges, banks of rivers, &c. ; flight 

 short, weak ; preys on small insects. Leptis, Atherix, Rhagio. 



Natural Order. — Therevites. 



Larva very elongate, with two air-tubes at the posterior extremity, 

 and the divisions of its segments very distinct ; inhabits moist 

 sand, mud and moss. Pupa changes in the same situations. 

 Imago, with the antennae composed of seven joints ; the basal 

 joint longer than the second, the remainin'g five united into one, 

 which is acute at the apex ; the labium is short, linear, and 

 bilobed ; the wings cover the body ; alulae obsolete ; body very 

 hairy. Inhabits the sand of the sea shore, roads, &c. making 

 short flights : preys on small insects. Thcrcm {Chr?jomyza.) 



