NOTES ON THE LIFE-HISTORY OF NEPTICULA ACETOS.E, STT. 105 



tapering down at the 8th. The 9th abdominal is much narrower, and 

 the 10th very narrow. In profile the head appears as a thin wedge, 

 and the prothorax is subtriangular. The mesothorax is heavily and 

 rather squarely formed, and carries a pair of large prolegs, the meta- 

 thorax being similar. 



The 1st abdominal segment is of lighter make, and does not appear 

 to carry prolegs, or if it does, the legs are very ill-developed compared 

 with the rest. The 2nd-7th abdominals (both inclusive) are each 

 furnished with prolegs, but the 10th abdominal has a rather slender 

 pair. There are no prolegs on the prothorax, and if there were, I 

 imagine, they would obstruct the larva when thrusting out the head 

 and prothorax while feeding. When out of the mine and crawling, 

 the larva of this species certainly makes use of the prolegs on the 10th 

 abdominal segment, but the larvte of some Nepticulids hold the 10th 

 abdominal quite free when crawling. N. centifuliella does so, and the 

 prolegs of the 10th abdominal are much less developed than in 

 iV. acetosae. None of the prolegs bear crochets, but those on the 

 thorax are each furnished beneath with a transverse row of three 

 tubercles, each bearing a seta directed posteriorly; these six tubercles 

 are in addition to the ordinary tubercles of the segment. The spiracles, 

 situated on the usual segments, are small, circular, not raised. In the 

 10th abdominal segment two rods may be seen. They are 0-09mm. 

 long, and lie close together at the end of the segment, but their 

 anterior ends are wider apart than their posterior ends. They occur 

 in all the four stadia. On the posterior surface of the 10th abdominal 

 there is a pair of spines, and below these another pair of longer spines. 

 In the larva of Trifurcnla htuinindella the upper pair of spines forms 

 part of a frame-work that runs round the posterior portion of the 

 10th abdomimal. From the inner side of the frame-work a pair of 

 flanges project, loosely connected with a pair of rods similar to those 

 above described. The anterior ends of the rods appear to be attached 

 to strong muscles. I have not seen this frame- work in the larva of 

 jN\ acetosae, but strongly suspect that it is present. The tubercles are 

 of moderate size, all simple, and the setsB all taper to a point. There 

 are no secondary hairs, but many skin-points on the lower parts of 

 the larva below tubercle iv. Tubercles v and vi are absent. In the 

 abdominal segments the arrangement of the tubercles is as follows : 

 i, the largest, is situated about the middle of the segment, taking it 

 lengthwise, but at some distance from the inedian line, that is to say 

 that the two i's are rather far apart ; the seta of this tubercle is very 

 stout, and 0-14mm. in length. Tubercle ii is slightly posterior to i, 

 and rather low^ down ; it carries also a stout seta 012mm. long. 

 Tubercle iii is anterior to i, just above, and a little in front of the 

 spiracle, it is very small, the seta being only O-OSmm. long. Below 

 the spiracle, and rather posterior to it, iv is situated ; this is rather 

 large, and its strong seta is O'lmm. in length. Below iv, and slightly 

 posterior to it, is vii, just above the proleg ; it is single, and the seta 

 measures 008mm. On the inner side of the proleg, a very small 

 tubercle, viii, lies, its seta is the shortest of all, being only 0-03mm. 

 Looking at the prothorax from above, we see two pairs of tubercles, 

 one on each side of the median line, a pair below each of these, and 

 then a single one lower still. These are all on the first large sub- 

 segment. On the second subsegment there is a large tubercle with a 



