THE ENTOMOLOGIST. 75 



either of the other shrubs, and depositing her eggs on these 

 and these only ; the eggs hatch in about foui'teen days ; thus 

 the 1st of May may be considered the earliest day for dis- 

 closure, but the periods both of oviposition and of emergence 

 frequently extend over three weeks or even a month, so that 

 during the month of June we find larvae varying greatly both 

 in size and age ; nevertheless, generally speaking, the cater- 

 pillar is full-grown at the end of June, and then rests in 

 nearly a straight ])osition on the leaves of the buckthorn. 

 Head small, decidedly narrower than the 2nd, and still nar- 

 rower as compared with the 3rd, 4lh and following segments ; 

 body widest at the 4th and 5th segments, and thence gra- 

 dually tapering to the caudal extremity, very convex on the 

 back and transversely wrinkled, slightly dilated at the sides 

 below the spiracles, and rather flattened on the ventral sur- 

 face ; the transverse wrinkles divide the back into sections, of 

 which every sixth is justdouble the width of either of the others ; 

 each segment has one wide and five narrow sections. Colour 

 of dorsal surface of head and body dull apple-green, much 

 resembling the leaf of its food-plant, but densely covered with 

 extremely minute black warts, each of which emits a small 

 short and slender white bristle ; the lateral dilatation is glau- 

 cous-green, terminating in a slender waved white stripe ; 

 spiracles very pale ; ventral surface, legs and claspers semi- 

 transparent apple-green ; the minute points are present, but 

 are much fewer, and therefore do not communicate the same 

 dull colour to the ventral which is observable on the dorsal 

 surface. About the 18lh of June it lightly covers the back of 

 a leaf or one of the twigs of its food-plant with a carpet of 

 extremely delicate white silk, and to this it attaches itself by 

 the anal claspers, forming also a surcingle or loop, the two 

 extremities of which are firmly fixed, close together, to the 

 silken carpet at the distance of a third of an inch from the 

 anal claspers ; this loop passes over the back of the larva, 

 supporting it equally well whether on an erect twig or the 

 horizontal under side of a leaf: this arrangement being com- 

 pleted, the lateral plates of the head separate, and the skin of 

 the back is partially ruptured, a green pointed protuberance 

 making its appearance through the aperture ; this green pro- 

 tuberance performs a slow but constant circular gyration, and 

 at every gyration the skin of the larva recedes towards the 



