221 [Mnrnli, 



ON THE MOULTING OF THE LARVA OP ORGYIA ANTiqUA. 

 BY T. A. CHAPMAN, M.D. 



I was led five years ago to make the following observations by 

 Mr. Ilellins having noted a variability in the number of moults this 

 species underwent. I was also interested in the general question, as 

 to how many was the normal number of moults in Lepidoptera, and 

 whether the larva in each skin was to any degree distinct and definite, 

 in the same sense that the larva is distinct from the pupa and that 

 from the imago. 



I may at once say that some of the larvro which I reared moulted 

 only three times, some four times, and some five times. 



^n its 1st skin the larva is very definite and easily distinguishable 

 (apa t from size) from those in the following skins, being black and 

 very similar to an Arctia larva, in that it possesses a set of tubercles 

 set with bristles, each tubercle and the hairs it carries being very 

 similar to its fellows. It differs from Arctia in one very important 

 point, viz., that each segment has only ten tubercles, instead of twelve 

 as in Arctia, and in a more conspicuous though less important matter, 

 namely, that the lateral tubercles of the second segment are very 

 prominent and large. But it has no trace of the tufts of barbed hairs 

 afterwards carried, nor any trace of the scarlet tubercles of the 10th 

 and 11th segments, though traces of these and some coloration are 

 distinguishable shortly before the first change of skin. 



In the 2nd skin it is equally distinct and definite. It is now 

 clearly of the Liparis family. The scarlet cups of the 10th and 11th 

 segments are very distinct, the lateral tufts of the 2nd segment are 

 represented by a few long special hairs, and the dorsal brushes of the 

 5th to 8th segments are represented by black pads (fused tubercles 

 as it were) with a few special barbed hairs ; all the hairs are still black. 



In the 3rd skin the majority are easily distinguishable. The sub- 

 dorsal tubercles are now pink, the barbed tufts are distinct on the 2nd, 

 on the back of the 5th — 8th segments, and on the 12th segment, the 

 tufts of 5th and 6th are dark, from fuscous to black, those of 7th and 

 8th are pale. 



In the 4th, 5th, and 6th skins the dorsal tufts are all pale in colour, 

 and the lateral tufts of 5th and 6th segments appear. Though the 

 latter are wanting in some, and in others there is a distinctly darker 

 shade on the dorsal tufts of the 5th and 6th segments. 



It thus happens that in a few of those in the 3rd skin there is a 



