Ohservaiiovs on Insects affecting the Turnip Crops. 63 



small pea^ and are attached to leaves of plants, &c. ; in these 

 they change to a pupa, and in about three weeks the flies come 

 forth in summer ; but the autumnal ones remain through the 

 winter in that torpid state. The case, it may be observed, is not 

 spun from the mouth, as the silk-worm forms its cocoon, but 

 from the apex of the body, similar to spiders ; and it is astonishing^ 

 considering the very ample wings of some of the flies, how they 

 can possibly be arranged in so small a space as they occupy in 

 their little cells. 



The flies are not long-lived, and the female deposits her eggs 

 in a very remarkable way, in order to protect them from the 

 attacks of parasitic and other insects. They are placed in groups 

 of ten or twelve, on various parts of the leaves, stalks, &c., and 

 so much resemble vegetable productions, that they have been 

 mistaken for the capsules or seed-vessels of some moss. It appears 

 that the female being supplied with a glutinous fluid in the 

 ovary, she places the apex of her body to the edge of a leaf, and 

 lifting it up, draws out a transparent thread, not thicker than a 

 hair, sometimes to the length of an inch, the egg forming a little 

 oval club at the tip (fig. 22). I ihink it extremely probable that 

 they are deposited while the female is on the wing by an undu- 

 lating flight, which brings her at intervals in contact with the leaf 

 or object beneath her; but I believe no one has detected this in- 

 sect in the act of depositing the eggs. 



The flies which we are alluding to are included in an Order 

 called Neuroptera, of the Family HEMEROBiD^i, and consti- 

 tute the Linnaean Genus Hemerobius, which is now divided 

 into four genera,* two of which, Chrysopa-j- of Leach, and 

 Hemerobius,^ are the groups which produce the larvae whose 

 history we have just given. The former genus contains ten or 

 twelve British species of beautiful flies, generally green, and well 

 known by their prominent, splendid eyes, whence they are called 

 with us golden-eyes. They fly principally at night, and are 

 heavy on the wing by day, so that they are easily caught ; and on 

 being touched they emit a most offensive odour. I will now de- 

 scribe the commonest species, which is named by Linnaeus 



17. C. Perla. It is a palish green; the horns are slender, as 

 long as the body, and composed of numerous small joints ; the 

 eyes very prominent, golden-green ; body moderately long ; wings 

 four, deflexed in repose, twice as long as the body, transparent 

 but greenish, reflecting the most beautiful rose-colour and rich 

 yellow, reticulated with innumerable hairy nervures, the trans- 

 verse ones blackish near the base ; legs six, very short and slender. 



* Curt. Guide Gen. 739, 740, 740^ and 741. 

 t Curt. Brit. Ent., fol. and pi. 520. % Ibid., 202. 



