348 MOTIONS OF INSECTS. 



Nepa ; Ranatra , and Naucoris of Fabricius. The pos- 

 terior tibiae of some of this last division (Lygcem phyl- 

 lopus, foliaceus, &c. F.) are furnished on each side with 

 a foliaceous process which may act the part of out- 

 riggers, and assist them in their flight a . I can give you 

 no particular information with respect to the aerial move- 

 ments of the insects of this order : the British species 

 that belong to it are generally so minute that it is not 

 easy to trace them with the naked eye ; and unless some 

 kind optician, which is much to be wished, would invent 

 a telescope by which the proceedings of insects could be 

 examined at a distance, there is no other way of study- 

 ing them. 



The four wings of the next order, the Trichoptera or 

 case-worm flies, both in their shape and nervures resem- 

 ble those of many moths b ; only instead of scales they 

 are usually covered with hairs, and the under wings, 

 which are larger than the upper, fold longitudinally. 

 Some of these flies, I have observed, move in a direct 

 line, with their legs set out, which makes them look as 

 if they were walking in the air. In flying they often 

 apply their antennae to each other, stretching them out 

 straight, and thus probably are assisted in their motion. 



The Lepidoptera vary so infinitely in the shape, com- 

 parative magnitude, and appendages of their wings, that 

 I should detain you too long did I enlarge upon so mul- 

 tifarious a subject. I shall therefore only observe, that 

 one species is described, both by Lyonet and De Geer c 

 (Lobophora hexaptera\ as having six wings; for besides 



a PLATE XV. FIG. 2. I have separated this tribe from the rest 

 under the name of Petalopus, K. Ms. b PLATE III. FIG. 4. 



e Lesser, L. i. 109, note*. De Geer, ii. 460. t. ix./. 9. 



