64 Observations on Insects affectlncj the Turnip Crojjs. 



Male, 4 lines long, wings expanding 1^ inch; female, ^ an inch 

 lono^, expanding nearly 1| inch. (Fig. 21.) 



This species is common about hedges, fields, gardens, and 

 orchards in June, July, and August. Last May I found one 

 of the larvae : its back was clad with lichen, the skins of cater- 

 pillars in fragments, and apparently its excrement : it spun a 

 white silken cocoon of exceedingly fine texture the beginning of 

 June, to the outside of which adhered the materials already 

 mentioned ; and in a week or ten days after, I found in the box 

 a fine specimen of the golden-eyed fly, of such dimensions that it 

 appeared incredible it should have been produced from so small 

 a pupa. A white transparent case or shroud, like those of the 

 May-flies, was lying by it, showing that it had emerged as a 

 pseud-imago.* 



The other genus still retains the appellation of Hemerobius, 

 and is more extensive, comprising, it is supposed, upwards of 

 thirty species. Their economy appears to be precisely the same 

 as that of Chrysopa ; for a larva which I found the end of last 

 September was feeding upon Aphides in company with the 

 maggots of the Syrphidae. It was of a bright yellow, with mark- 

 ings of a clear rust-colour : it was very active, continually moving 

 its head from side to side, and eventually produced a species 

 named by the late Dr. Leach. 



18. H. obscurus. It is ochraceous; the horns are rather 

 longer than the body, slender, hairy, composed of numerous 

 globose joints; eyes very prominent; head and trunk with a 

 brown stripe on each side ; abdomen of the same colour : wings 

 nearly twice as long as the body, very much deflexed when at 

 rest, slightly tinged with fuscous, but with a beautiful blue and 

 rose-colour; superior, with numerous pilose nervures dotted with 

 dark brown, having two irregular waved transverse lines of a pale 

 brown-colour beyond the middle ; inferior wings of a lovely rose- 

 colour, the margin alone iridescent and brownish : legs 6, and 

 rather short : about 3 lines long, and expanding 8. 



These insects frequent every hedgerow and plantation, and 

 from thence they fly by night into fields, meadows, gardens, &c., 

 aud they are sometimes plentiful in turnip- fields. They are 

 always very brisk and lively on the approach of a thunder-storm ; 

 but when caught, they lie with their wings closed and compressed, 

 and their horns and legs drawn up, as if they were dead, some of 

 them looking, in that inanimate state, like dead leaves. 



We shall close this account of the insects which feed upon 

 Aphides, by giving the history of the larvae of several flies called 

 Syrphi, which appear to be more numerous than the lady-birds 



* A state between the Nympha and the perfect insect or Imago. 



