Of all the Orders, that of the Lepidoptera is by far the most difficult 

 to form into genera, in consequence of the parts of the mouth being 

 frequently imperfect, and closely covered with scales or hair ; and 

 the characters to be derived from the habits of the species will only 

 supply the materials for forming larger groups. Latreille in his 

 various works has comparatively done little in the arrangement of 

 this beautiful Order, which appears to have been the favourite of 

 the collector and the outcast of the scientific. Savigny indeed is 

 never to be forgotten for his inimitable dissections, so exquisitely 

 delineated in his " Memoires sur les Animaux sans Vertebres" ; 

 and it is to be regretted that his labours were limited to the com- 

 parison of the analogous organs of some of the Orders only. 

 Schrank has instituted many good genera, as well as Ochsenheimer 

 and Germar ; but the characters of the former are often very un- 

 satisfactory, and the latter frequently gives nothing more than a 

 type of the group. With such assistance it is with difficulty that the 

 genus to which a lepidopterous insect belongs can be determined. 



Upon a carefid revision of the insects which were at first in- 

 cluded in the genus Odonestis, I am disposed to agree with Ger- 

 mar that Pini and Potatoria may fairly be considered as types of two 

 genera; and as he proposed a name in 1811, and Hiibner not till 

 1822, and then included the above two insects, thereby merely su- 

 perseding Germar's name, I have restored that which has the right 

 of priority. As I shall not publish a plate of O. Potatoria, I shall 

 give that genus in the next leaf. 



When we were at Marseille the end of June, Mr. Walker found 

 two caterpillars of D. Pini feeding on pine-trees; the hairs with 

 which they were clothed caused excessive irritation when handled, 

 and they were more like those of Gastropacha quercifolia in form, 

 and of a more uniform colour than Hiibner's and Roesel's figures, 

 and very much powdered with white ; the moths were produced 

 the end of July, and were very gray. 



About the middle of September 1748, Mr. Wilkes found a cater- 

 pillar of D. Pini upon a white-thorn bush near Richmond Park, 

 which lived through the winter without eating; and my friend 

 Joseph Sparshall, Esq. took a fine male moth in the Norfolk and 

 Norwich Hospital, 22nd of July 1809, and I was indebted to him 

 for being able to give a representation of it ; a British specimen 

 never having been elsewhere figured. The example in the col- 

 lection of N. A. Vigors, Esq. was from Beckwith's cabinet, and the 

 female in my own possession from Mr. Plastead's. 



Being desirous of making this work as complete as possible, I have 

 introduced a copy of the female caterpillar from Roesel, who says 

 that it feeds upon Pimis sylvesiris and P. Strohis ; that in June it spins 

 a cocoon, and three weeks after the moth appears. The cater- 

 pillar of the male is said to differ very much from that of the female. 



Pimis si/lvestris (Scotch Fir) is represented in the plate. 



2 



