SOLENOBIA FROM NEAR READING. 173 



pro- and niesothorax, though there are other hah-s present as well) 

 each hearing many hairs ; but I can only trace two small dorsal hairs 

 on each abdominal segment. The arrangement on the metathorax is 

 suggestive that the Lepidoptera may have received the primitive 

 arrangement of tubercles from an ancestor common to the Lepidoptera 

 and Trichoptera. If this assumption were correct the arrangement on 

 the lepidopterous pupa should follow the trapezoidal i)lan indepen- 

 dently of the larva. In Macro-Psychid larvie the larval tubercles are re- 

 versed as to position, the base of the trapezoid l)eing towards the head and 

 the smaller end towards the anus, and this is the case in the pnjia alsti. 

 This fact would appear to suggest that the determinants which produce 

 the pupal characters are influenced by the more recent larval ones ! 



In the Liparids, belonging to a much more specialised family, we find 

 that the pupal hairs ('? rather an uncounnon feature for so specialised 

 a group) follow the position of the larval tufts, or tubei'cles (/.c, where 

 we get a tuft in the larva we get a tuft, or something approaching one, 

 in the pupa). This w^ould seem to support the former suggestion, but 

 when we come to the hairs themselves a new feature is apparent. The 

 pupal hairs differ in structure from those of the larva. In the Liparid 

 laivie that I have examined all the larval hairs (so far as my know- 

 ledge extends) are thorny, branched, or plumose, and circular in 

 section, while the pupal hairs are (with three exceptions to be noted 

 later), Avithout thorns or branches, and are frequently fiat or ribbon- 

 like. In Notolophns anti(]i(a and X. i/dnostiiiiiia, the situation of the 

 larval dorsal tufts is occupied in the pupa by structures which are not 

 hairs at all in the usual sense of the word, although they may be 

 homologous in a physiological sense. The three exceptions to be noted 

 are as follows : — l.ipnantria and f'orthetria, in both of which the pupal 

 hairs are thorny, whilst Lenctnna solids also has a few of its hairs of 

 this character. These pup* are, however, greatly exposed. In the 

 case of L. nionacha and /'. dis/iar, they are suspended in a slight 

 silken hammock, while the cocoon of //. saliris is often very slight. 



The pup;e of I'mtltesia aiirifiiia and /*. chri/sorrhoea are well pro- 

 tected by the irritating larval hairs in the cocoon, and we find these pupje 

 are less hairy than those of the other Liparids. The above facts appear 

 to point to the pupal hairs of the Liparids having a special and inde- 

 pendent development, quite apart from those of the larva, only we 

 must not forget that Pasi/chirafasrelina, which has the stoutest cocoon 

 of any of the British species, is the most hairy of all, and, further, 

 that we have still the position or arrangement, so similar to that of 

 the larva, to account for. 



Is the stimulus (if any) of the position of a tubercle or tuft in the 

 larval skin sufficient to determine where on the pupa the independent 

 or ancestral pupal hairs shall develop, or must we look for an explana- 

 tion to a (?) possible mixing of larval determinants with the pupal 

 ones, and, if so, what prevents imaginal ones from doing the same ? 

 Or, finally, are we to consider the pupal envelope a hybrid structure, 

 partly ancestral imaginal and partly modern larval ? 



Critical notes on a Solenobia from near Reading. 



]3y J. W. TUTT, F.E.S. 

 I have recently been at work on the Solenohiar, and have had to 

 critically review the literature thereof. As I shall have to disagree on 



