the Pupa of Trocliilium andren^&formis. 481 



O'l mm. and about half their length wide at base (those in front 

 two-fifths). The length of the base is nearly the same as the height 

 of the spine ; the form of the spines is much that of a rose-thorn 

 but straighter and thicker, the front sloping backwards in a .straight 

 line, the back hollowed in a curve, but vertical to the surface of 

 origin. The general surface is smooth, but very minutely tessellated 

 like the thorax. The last (tenth abdominal) segment is not very 

 definitely marked off' ventrally from eighth and ninth. The curva- 

 ture of the pupa and especially of this segment makes its termination 

 rather ventral than posterior. It has a ring of eight strong spines 

 round its margin, almost equally spaced, except that the space 

 between the two ventral ones (3 and 4) on each side is rather less 

 than the others. Each of these is about 0*1 mm. high, but stands 

 on a little eminence making it twice as tall. All face to the centre 

 of the segment, round which they form as it were the spikes of a 

 crown ; each rises outside by a convex slope, on the inner side the 

 face is a hollow, with a ridged margin; it terminates in a neck 

 rather bent inwards, the end being the base of a hair, which in each 

 case points to the centre of the segment. The hair is about O'l mm. 

 long. Looking from behind or rather from below to the centre of 

 the ring formed by these spines, the space is occupied by a rounded 

 swelling, higher above (posteriorly), where it is rather full and 

 rounded (the obsolete cremastral spike). The front half has the 

 longitudinal anal scar with some lateral parallel ridges and some 

 radiating wrinkles into the boss behind. The whole width of the 

 ninth segment has a longitudinal ventral suture a little widened 

 against eighth. The eighth has an obscure ventral flattened smooth 

 space notched at each margin, but with little trace of line or pore. 



In dehiscence the fracture is down the median dorsal line through 

 dorsal head-piece and through the whole thorax. The front head- 

 piece separates from these and the antennae lift out clear ; the head- 

 piece is held in place by the maxilla, whose extremities remain 

 in situ, and by mere shreds connecting it with the first femora and 

 legs; the femora separate except at their extremities being held to 

 the tibia at one end and to the head {prosternum really) at the 

 other. The eye-piece separates and forms a last element of a chain 

 held together by membrane of mesothorax, pronotum, and dorsal 

 head-piece. Essentially nothing is ruptured except the dorsal suture, 

 and the dorsal from the ventral head-covering ; though also no doubt 

 much sternal delicate membrane interiorly suffers. 



