Annual Address of V. T. Chambers, Esq. 85 



twice as long- as it was at tlie close of the first stage. Its mine is still 

 circular, and 2.38 mm. in diameter, or just twice the diameter that it 

 had at the end of the first stage. , 



The area, therefore, is 4.4528 mm., or just four times what it was at 

 the end of the first stage. But the mines of the first stage is included 

 in this area, and, therefore, the amount of mined surface which repre- 

 sents the food consumed in the second stage, is just three times as 

 great as it was in the first sta2;e; while as just stated the larva has 

 only doubled its length, but then it has grown in other directions 

 also. The second moult proceeds precisely like the first, which I have 

 alread}' described. Sixty hours have been spent in feeding, and then 

 twelve are spent in moulting. Three da3's is the entire length of this, 

 as of each of the first five and of the seventh stages. The larva of the 

 third stage resembles at first that of the second closely, and is but 

 little larger. The maculiB, however, are darker, and the maculated seg- 

 ments are of a deeper smoky hue, and the macula on the fourth seg- 

 ment is trapezoidal, instead of elliptical. Sixty hours more are occu- 

 pied in feeding, and twelve in moulting, and the larva at the close of 

 this stage measures 2.4384 mm., or three times the length of the larva 

 at the end of its first stage. The mine at this time usually departs 

 somewhat from its circular form, but occasionally circular mines of 

 this age may be found, and these have diameters of 3.57 mm., or three 

 times the diameter of the mine of the first stage, and have an area of 

 17.711 mm., or four times the area of the mine of the second stage 

 which, however, is included in it, so that the area mined in the third 

 stage, and which represents the amount of food consumed in it, is three 

 times as great as that mined in the first and second stages combined. 

 The process of moulting is precisely as in the two previous stages. 



In the fourth stage, the macule are still more distinct, and a new 

 trapezoidal macula appears on the third segment, and the maculated 

 segments are of a still deeper smokj' hue. But the form of the mine 

 is now so irregular that its area can not be accuratel}' determined; still 

 one can easily determine that if it is not exactly four times as large as 

 it was at the end of the third stage, the difference must be very small 

 indeed, and I am convinced that the same ratio still prevails. The 

 length of the larva at the end of the first stage has again been added, 

 and at the end of this, the fourth stage, the larva is four times as long- 

 as it then was, that is, it is now 3.35 mm. and a fraction. Sixt}^ hours 

 have again been spent in feeding, and twelve in moulting, and the pro- 

 cess of moulting is precisel}^ what we have seen it to be in the three 

 previous stages, and the larva enters its fifth stage. 



