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case, but by the destruction of the internal pulpy substance or parenchyma of the leaf, 

 while the cuticle or skin, both above and below, remained entire. When a leaf was 

 held between the eye and the light, there could be seen, through the discoloured but 

 seraitransparent cuticle, a little, whitish, flattened grub, which had devoured the pa- 

 renchyma, and lay enclosed in the cavity thus formed between the two layers of skin. 

 On being disturbed, this insect moved, with a wriggling motion, from one part of its 

 retreat to another, backwards quite as readily as foi-wards. The shape of the spots was 

 irregular, and they varied somewhat in size ; but on an average, each one might have 

 been about an inch square. Several leaves containing larvfe, among which was one 

 that had already passed into the pupa or chrysalis state, were shut up in a box. Soon 

 afterwards the insects passed through their transformation, and, leaving the cast-off 

 pupa-skin nearly entire, within the cavities which they had occupied, they made irre- 

 gular perforations through the dried cuticle, and came out upon the surface of the 

 leaves. The insects, thus disclosed in the perfect or winged state, proved to be little 

 beetles belonging to the genus Hispa ; but as they were subsequently lost, it is not in 

 my power positively to identify them with any of the species now in my collection. 



" In June, 1827, I discovered a leaf of the poplar-tree which contained a small 

 dead larva, very closely resembling that of the Hispa of the apple-tree ; but it was not 

 till the 17th of July, 1829, that an opportunity of observing in detail the habits of 

 these insects again presented itself. Upon this day I found larva, like those of the 

 apple-tree, feeding, in the same manner, upon the parenchyma of the leaves of the 

 white oak. Each one of these insects, when fully grown, measured from 20 to 27 hun- 

 dredths of an inch in length. The head was horny and of a brownish black colour ; 

 the body, consisting of 11 segments, flattened and broad near the head, 

 ^^^ gradually narrower behind, was yellowish white, except the greater part 

 ^ J "^ ^^^ upper side of the first segment, a spot in the middle of the under 

 'Jj side of the same, and the upper part of the tip of the last segment, which 

 were dark brown or nearly black. The head was small in proportion to 

 *__ y the size of the first segment, and partially drawn within it. Minute an- 

 tennge were perceptible, and the jaws were short, strong, somewhat tri- 

 angular, and simple or scarcely indented within. The legs were six, 

 short, and of a brown colour, a pair beneath the first, second and third 

 segments. The other segments were dilated at the sides, and terminated 

 by small brown tubercles. Above these lateral mammillary projections 

 was a series of seven smaller ones, each bearing a spiracle or aperture for respiration. 

 The second segment, at the sides, near its anterior edge, was furnished with two large 

 spiracles, and two, still larger, were situated upon the upper part of the terminal seg- 

 ment, near its tip. The fourth and remaining segments, except the last, had, both 

 above and below, a transverse callous spot, covered with minute projections like a rasp, 

 which appeared to be designed to aid the insect in its motions. On the 5th of August 

 five of these larvae were transformed to pupae, four of which assumed the perfect state 

 on the 1 1th, and the 5th on the 12th of the same month ; from which it appears that 

 the pupa state lasts only six or seven days. The colour of the pupa was a yellowish 

 white, but, as it approached the period of its final change, the body became reddish 

 and the wing-sheaths brown. Its body was rather shorter and broader than that of the 

 larva ; the abdominal segments were tuberculated at the sides, and were furnished, 

 both above and beneath, in the centre of each segment, with a transverse series of ele- 

 vations, much larger and more prominent than those of the larva, and tipped with 



