84 Cincinnati Sociefy of Natural History. 



the size of the mine in the previous stage, which is the same thing as 

 saying that the quantity of food consumed by the larva in each stage 

 always bears the s ame definite ratio to the quantit}' consumed in the 

 preceding stage. In each stage it is three times as much as in all of 

 the preceding stages combined; and that at the end of the 2d, 3d, 4th 

 and 5th stages respective!}', the length of the larva is increased b}^ ex- 

 actl}^ the length of the larva at the end of the first stage. I have said 

 that about sixty hours after the larva leaves the mine, it ceases to feed, 

 and places itself across the Y to undergo its moult. At that time it is 

 j-ellowish white, without maculfe, and with mouth parts as in figs. 1 

 and 2, and no trace of the larva in its 2d stage, is discernible; but in 

 three or four hours, the skin is seen to be somewhat loosened over the 

 posterior segments, and the antennae and trophi are seen to be parti}- 

 retracted out of the corresponding parts of the old skin. The body, 

 when the larva ceases to feed, is composed largely of oil globules, which 

 at first are packed densely along the course of the intestine, but after- 

 wards spread and make their way through the tissues, forming two rows, 

 extending through the entire length of the larva, even down into the 

 trophi, and which send out on each side two rows into each segment. 

 These oil globules are gradually absorbed into the tissues of the 

 body; and by the time the organs are retracted as above stated, the oil 

 globules have almost entirely disappeared. The separation of the 

 contained larva from its old skin appears exactly as if the inner layer 

 of the skin, over the whole extent of the body, had separated from the 

 outer one. After the various organs are retracted as aboA^e stated, they 

 are at first soft, white and colorless, but they rapidly harden, and the 

 trophi assume a ferruginous hue, and the larva begins to struggle for 

 release from the old skin, which ruptures across the under side of the 

 suture behind the head and then down the sides; and twelve hours after 

 it ceases to feed, the larva makes its exit from its old skin. It is then 

 but little larger than the larva of the first stage, but it immediately, 

 sometimes before it is entirely free from the old skin, begins to feed vo- 

 raciously. The oil globules have now entirely disappeared. The larva 

 is at first yellowish white, without macuhx), but in a few hours the 

 hollow elliptical transverse maculae begin to appear on segments five to 

 nine inclusive, and soon they are distinct on both the dorsal and ven- 

 tral surfaces of the body, though they are less so on segments 4 and 9 

 than on the others, and these maculated segments assume a faint, dusky 

 hue. After feeding and growing another sixty hours, the larva again 

 ceases to feed, and retires to the central spot (no longer Y shaped) 

 lo undergo its second moult. It is now just l.G25fi mm. long, or just 



