104 



Observations on the various Insects 



shorter, cylindrical, elliptical, and of a dull ochreous tint, be- 

 coming darker as the period approaches of the birth of the fly : 

 the antennae, eyes, wings, and legs are visible beneath their horny 

 sheaths (fig. 52; u, the natural size). At this period they are 

 deprived of locomotion, but the larvae, although perfect maggots 

 and destitute of feet, are able to move along in moisture, at the 

 same time waving about and thrusting out their heads with great 

 energy. There are 30 species of these flies which inhabit Eng- 

 land, and 3 or 4 of them have been bred from putrid potatoes. 

 One is called 



30. Sciara fucata, Meg. ;* when alive it is 1 line long. The 

 male is of a pale inky- black, the head is small and spherical, with 

 2 tri-articulate feelers bent under ; the 2 horns are not longer than 

 the thorax, tapering, pubescent, inserted in front of the face, and 

 16-jointed, 2 basal joints the stoutest, the remainder oblong, apex 

 conical ; eyes lateral, kidney-shaped, and coarsely granulated ; 

 ocelli 3, but unequal : trunk gibbose, subquadrate, scooped out at 

 the base, with two indistinct lines of short ochreous hairs down 

 the back ; scutel lunate, postscutel oval, of a greyish colour : ab- 

 domen slender, greenish black, brownish after death, 7-jointed, 

 the margins of the segments pale, apex obtuse, and furnished 

 with 2 incurved bi-articulate lobes : 2 wings, incumbent in repose, 

 parallel, longer than the body, iridescent, slightly smoky, but 

 transparent and clear at the base ; nervures brown, excepting the 

 central one, which is scarcely visible, but forked and dark at the 

 margin ; the costal nervure does not reach the base of the forked 

 cell : balancers pale dirty yellow or ochreous : 6 legs, long, slen- 

 der, and of a dirty yellow or pale olive tint. Female similar, but 

 iarger, being 1^ line long, the wings expanding nearly 3 lines: 

 the thorax is not narrowed behind : the abdomen is spindle-shaped, 

 attenuated, and conical, terminating in 2 little parallel sheaths: 

 the 2 balancers are dusky when dry. 



This was bred in the winter of 1845-46, and again in 1848, 

 in vast quantities : the flies are also found throughout the summer 

 in fields and gardens, on umbellate flowers, and on grasses. I have 

 likewise bred them from rotten turnips in March. 



31. S. quinque-lineata of Macquartt is i\ line long (fig. 53, 

 the female ; v, the natural dimensions). " It is black, with 5 lines 

 on the thorax of a deep dull grey : anterior hips testaceous : 

 wings almost hyaline balancers brown or dirty white. 



Specimens agreeing with this description were bred from rotten 

 potatoes in March, 1848, and sent to me with the tubers con- 



* Meigen's Syst. Besch. Europ. zweif. Inseck., vol. i. p. 280, No. 6, and 

 Gardeners' Chron., vol. v. p. 784. 



f Hist, Nat. des Ins. Dipteres, vol. i. p. 149, No. 10. 



