THE I,ARVA AND PUPA OF JIALACOSOMA ALPINA. 



285 



active, yet the larv<e are capable of moving at veiy considerable speed 

 on occasion. The most forward of the larvic began to spin up about 

 July 25th, but the more backward ones are now (August 9th) only 

 feeding slowly, and making but little progress. Probably the method of 

 treatnient, added to the vicissitudes of travelling, is not to their taste. 

 The full-grown larva in its last instar extends from l-25mm. to 

 l-50mm. in length ; tapers slightly from the 3rd abdominal segment 

 to the head, and less so to the anus, so that it is fairly cylindrical. 

 The head is only rather less in width than the prothorax, dull, deep, 

 leaden-grey in colour, covered all over with brown hairs, considerably 

 shorter'' than the longer ones on the body ; the surface of the head is 

 covered with a number of minute black spots (aggregated m little 

 groups of from three to six) which do not seem to be related to the 

 hairs in any way. These little groups of spots are again aggregated 

 into two rows on either side of .the median suture, but not reachmg 

 quite to the clypeus ; outside these two rows are two parallel areas of 

 about the same width without any spots, the latter bemg contmued m 

 less rec^ular rows over the rest of the head. There are six black shmy 

 ocelli on each cheek— one median, four others forming a curve outside 

 it and one in the same line of curve as the last named, but much 

 above them. Some larvai have the fifth and sixth of these ocelli 

 absent The antenna- are black with whitish segmental incisions and 

 a white base. The labrum is shiny black, and between the labrum 

 and the clypeus is a small shiny black piece (= ? the parclypeal piece). 

 The other chitinous mouth-parts are black with paler incisions ; there 

 is also a verv marked spinneret. The true legs are black with very 

 numerous fine brown hairs scattered over their surface ; each leg 

 consists of a fleshy base, a very narrow chitmous piece, then three 

 ioints (graduallv becoming smaller) and finally a semitransparent pale 

 brownish claw.'' The prolegs consist of two large basal rings of soft 

 tissue, and then a long extensile joint carrying a row of aJjout ^4 

 strou'^ brown hooks. The anterior subsegment of the prothorax is 

 pale, 'and on either side is a lateral projection which may represent a 

 tubercle, otherwise the longitudinal disposition of the lines and 

 markings appears to be similar both on the thoracic and abdominal 

 segments. The larva is clothed with brown hairs, not at all densely 

 enou-h to obscure the larval skin which gives the animal its colour. 

 Thp 'len-th of the brown hairs is very various (the longest rather 

 more than half the diameter of the larva in length, except on the /th- 

 9th abdominals, on which many hairs are fully as long as the diameter 

 of the larva). In the disposition of the hairs no special arrangement 

 with regard to tubercles, subsegments, &c., can be traced ; ventrally 

 the hairs are sparser and shorter. Looked at dorsally, the larva 

 shows a blue hne on each side, a broad chocolate band above his, and 

 a median whitish-yellow line broken up by some minute b ack dots 

 (hair-bases). In most specimens there is a narrow, irregular, very 

 fine, brownish-red line, close to either margin of he median Ixind and 

 to be detected on the anterior segments. These lines ai^ much more 

 pronounced and continuous in younger larva", which, therefoi;e. resemble 

 nioreclosolv the larvaof M. nmstria. The spiracles are situated on a bioad 

 blue band, touching, immediately beneath, a naiTOW yellow one ; above 

 the blue band is a narrow chocolate ^'^nd with a brmvn line in the 

 middle of it, and above this is the narrow blue band alre.idy doscubed 



