20 NATURAL HISTORY 



They feem to prefer different trees in different places. 

 In my neighbourhood the common red Cherry was more 

 attacked, than the Plumb or Pear : in a garden about a 

 mile diftant, they feemed more pleafed with the Quince, 

 than with the Pear, Cherry or Plumb: In another place 

 the Button-Pear was preferred to any other. I have alfo 

 found them on the wild Black-Cherry and wild Pear. 



The largeft (lugs that I have feen, were about 9-20ths 

 of an inch in length. The head of a dark chefnut colour, 

 is bent under and entirely concealed (fig. 3 8z 4..) This 

 conformation is neceffary as the direclon of its bite is in 

 the plane of the leaf; but when it has alTumed the yellow 

 coat, its head is more prominent and ,difcernible (fig. 2. 

 b. Scfig. 5J The fix firft: feet are terminated with a lit- 

 tle hook ; befides thefe there is a limb on each fide, be- 

 tween the firft pair of feet and the head, which is unarm- 

 ed, and always laid over the fide of the face juft below 

 the eyes. I have not obferved any thing analogous to 

 thefe in any other larva; they are fhewn at fig. 4. a : 

 their ufe may perhaps be to regulate the depth of its bite, 

 and to wipe off any extraneous particles that may adhere 

 to the jaws or antennae. The other fourteen feet are en- 

 tirely unarmed (fig. 3. b.) It is mechaincally fupported 

 by the former ; but its fupport by means of the latter ap- 

 pears to depend on the preffure of the atmofphere. 



Their body is largeft towards the head, and diminishes 

 gradually toward the tail. They have the faculty of 

 f welling out the anterior part of the body (as in fig. 2. a. 

 Scfig. 3.), and they moft frequently appear in this man- 

 ner with the tail a little turned up (fig. 2. a). 



The cell is reprefented at fig. 7 ; the pupa is yellowifh, 

 the eyes brown and is delineated at fig* 6. 



The fly is of a full gloJJ'y black except the legs which 

 are of a brownijh ajh colour : the antennae black with nine 

 articulations. It is reprefented at fig. 8. a, of its natural 

 fize, and magnified at fig. 8. b. The wings are tranfpa- 

 rent, with a footy tinge, reflecting the priimatic colours 

 when held in certain directions to the light. They are a 

 little tumid or convex on the upper fide, which is one 

 charaQeriltic of this genus; but a more certain one is 



the 



