428 BRITISH LEPIDOPTERA. 



extremely minutely, sculptured by fine lines, and the nervures are easily 

 seen. Poulton's line cuts off a narrow (imm.) margin, The meta- 

 thorax presents two great characteristic callosities. These are oval 

 (except that they almost meet in a point dorsally), about 5mm. 

 each across and i - 8mm. from front to back ; except a median ridge, the 

 rest of the segment is very smooth though it may have a few 

 irregularities. The callosities are as though a layer of pitch had 

 been put on, and circular pits of some depth impressed in it so 

 closely as to deform each other and leave between them narrow 

 sharp ridges, the pits about o^mm. wide. The floors of the 

 pits are level, so that the ridges between them might be described 

 as walls of fairly uniform thickness. The narrow strip of the hind- 

 wings recedes from the 2nd abdominal spiracle and disappears opposite 

 that of the 3rd segment. The abdominal segments are less smooth than 

 the thoracic. Their anterior margins are pitted most strongly dorsally, 

 the rest of each segment is wrinkled in fine transverse lines, with 

 fine pits slightly intruding. On the 7th abdominal segment the pits reach 

 the hind margin. Subsegmentation is not well marked, the interseg- 

 mental subsegment is easily distinguished on the 3rd abdominal, and 

 on the 1st and 2nd an anterior subsegment is fairly distinct, the inter- 

 segmental one less so, whether the intermediate area is or is not 

 subdivided is largely a matter of personal equation, but in some 

 degree of the specimen examined. The most notable features of 

 the abdominal segments, and in some degree of the pupa itself, are 

 the prespiracular flanges on segments 5, 6 and 7, largest on 5 and 

 smallest on 7, they are otherwise almost identical on the three 

 segments. The flange consists of a sharp edge about 5mm. long ; 

 in front of this edge the surface is flat, smooth, and facing directly 

 forwards, with a width of about imm., behind, the surface is rounded, 

 but may better be described by saying that the surface of the 

 segment, instead of being curved down to the incision, continues 

 directly forwards, with very little final outward curve to the sharp 

 margin of the flange. When the segments are flexed, the anterior 

 flat surface of the flange comes against the posterior margin of the 

 segment in front, which is full and rounded in such a way that 

 the flange fits against it, and the side of the pupa is smooth and 

 level. On the opposite side, where the segments are extended, each 

 incision is rather a deep gap, with the flat surface of its posterior 

 lip directed forwards, and the margin is a very sharp edge. One 

 cannot help noticing that the side of flexure will slip smoothly on 

 anything, but that the extended side presents a series of notches 

 with very sharp, almost hooked, margins, and flat surfaces on their 

 posterior edges, so as to present a determined impediment to the 

 pupa slipping forwards. This is at once appreciated on drawing 

 the finger along the side, first flexed then extended. There can 

 be no doubt that these flanges, developed in some Eumorphids 

 to enable the pupa to leave the puparium, have here precisely the 

 opposite function, 772., that of a cremaster, to prevent the pupa- 

 case accompanying the moth on emergence. The spiracle lies in 

 a little hollow behind the anterior portion of the flange. In front 

 of the flange is a little series of curved transverse rugae. The 

 ordinary form of the cicatrices of prolegs on 5 and 6 is as slightly 

 depressed smooth areas with faint striai or wrinklings radiating from 



