272 BRITISH LEPIDOPTERA. 



We have already referred (ante, p. 108) to the observations of 

 Standfuss on the pupation of Stenophanes graslinella, and the double 

 moult undergone by it previous to its taking on the pupal form. 

 Standfuss notes a case, spun-up for pupation, and obtained on April 

 12th, that contained a larva with the head towards the spun-up end of 

 the case ; on April 21st a larval skin was seen hanging from the free 

 end of the case, the larva had reversed its position and now had its 

 head towards the free end. On May 6th the case contained a still soft 

 pupa, which on June 7th produced a crippled male. He notes that the 

 male larvae of viadrina, stetinensis, hirsiitella,&n&standfussi, also remain 

 for some time after the case is spun-up with the head towards this end, 

 that they moult in this position, then turn round, remain quiescent for 

 some time, and then moult again and become pupae. The females of 

 the same species, he asserts, turn round as soon as the case is spun- 

 down for pupation, and change to pupae by a single moult. The larvae of 

 both sexes of unicolor, villosella, and opacella, act as do the female larvae 

 of the preceding. Of this Heylaerts writes : " J'ai trouve la meme 

 chose non seulement pour les especes dont les fourreaux males ont un 

 tuyau de soie tres long, mais aussi pour plusieurs autres. J'ai fait des 

 recherches multiples sur P. graslinella, P. villosella, P. hirsutella, and 

 P. ecksteini. J'ai trouve des chenilles, quittant leur avant-derniere 

 peau dans la position precitee, qui m'ont donne le papillon plus tard. 

 Le doute n'est done plus permis. Seulement, la femelle aussi change 

 de peau avant de se retourner." 



The digest that we have already given of the more important work 

 tbat has been published on the Palaearctic Macro-Psychids leaves some 

 points on which our own conclusions may be stated briefly. The males 

 of the lower Macro-Psychids are better scaled, and the presence of hair- 

 scales may be looked upon as a specialised character. The suppression 

 of the posterior tibial spurs is also a sign of specialisation, and has 

 undoubtedly been brought- about side by side with the modification of 

 the female, and has been due to the necessities involved in copulation 

 with females that do not leave the puparium for this purpose, and 

 Chapman is inclined to consider that the structure of the tibial spurs 

 forms the best basis for the classification of the Macro-Psychids, if 

 male imaginal characters are at all sufficient for the purpose. The 

 anterior tibial spines or spurs in particular have not been valued by 

 systematists as they deserve ; they have, indeed, found them rather 

 troublesome on occasion as not confirming neurational and other 

 characters, but there can be no doubt that they are as valuable for classi- 

 fication (as far as they go) and as good (or bad) for that purpose as 

 any other character. They necessarily conform to ordinary evolutional 

 rules, so that species, having any special form of these spurs are 

 prima facie related, and if any species has lost them, it cannot be on 

 the ancestral line of one that still possesses them. They possess the 

 apparent peculiarity of being lost per saltum in many instances. This 

 is a peculiarity that is common to all articulate forms and organs. 

 Tarsal joints, antennal joints, joints of other articulate organs, even 

 actual segments, present many instances of being lost apparently 

 per saltum (discontinuously). An antennal joint may be regained, not 

 probably actually, but apparently, by the formation of new joints, 

 always possible so long as any joints are left. The anterior tibial 

 spur, however, has only one joint, and, once gone, cannot be repro- 



