460 BRITISH LEPIDOPTERA. 



has joined the discal cell, leaving vein 7, again arising from it, but before the tip of 

 the cell. 



Phylum J is a group not represented in England, intermediate between phyla 

 B and D. The larva retains most of the characters of phylum B, though they are 

 generally less strongly developed, while the moth has assumed the venation of 

 phylum D." 



With much that Dyar writes we are in evident agreement. His phyla 

 A and D make up the bulk of our Pakearctic Lachneidae, his phyla B, C 

 and J the bulk of our Pakearctic Eutrichidae. When, however, it comes 

 to a consideration of detail we are at issue on many points. Dyar 

 essentially makes his phylum C the generalised section of the Eutri- 

 chids, with which we are somewhat in accord, but when he would 

 derive the neuration oiEpicnaptera (phylum B) from that of Cosmotriche 

 (phylum C) we can only demur. We presume that these genera, having 

 reached a certain point of development in common, have then gone on 

 independently to their present forms. Certainly in the direction of the 

 specialisation of the supplementary cell at the base of the hindwings 

 and the supplementary nervules arising therefrom Eutricha has 

 specialised much further than Cosmotriche, and presents with Gastropacha 

 (Epicnaptera) the most highly developed neuration of the Eutrichid 

 (and Lachneid) stem. The specialisation of this supplementary cell 

 and its nervures may be readily traced from the plates by Aurivillius 

 (Iris, vii., pi. 3-4 ). Our own notes of the neuration read as follows: 

 The supplementary cell, placed just above the base of the median cell 

 of the hindwing is very small in Poecilocampa and Trichiura, with one 

 small nervule branching from its upper edge in Trichiura and two in 

 Poecilocampa. The cell has a similar character in Lachneis, but there 

 is considerable modification in the upper branching nervule. The cell 

 is also simple in Malacosdma, somewhat elongated in Lasiocampa and 

 Paclnjpasa, and the same conditions are noticed in all those genera that 

 have no great extension of the basal area of the hindwings. When, 

 however, we turn to the Eutrichids, in which this extension is most 

 marked, the cell gradually becomes modified, maintaining its simplest 

 form in Dendrolimus in which the costa of the hindwing is almost 

 straight, and having only one small upper nervule arising from it. 

 Odoncstis is but little in advance of this, but Cosmotriche shows 

 considerable development and gives rise to three branches, the extended 

 cell separating the (normally) branched nervure arising from it into its 

 two constituent parts. In Gastropacha (Epknaptera) and Eutricha the cell 

 and the supplementary nervules are remarkably specialised, the latter, 

 perhaps, being the most specialised of all. Intermediate stages of 

 development are well illustrated by Diplura and Selenephera, the latter 

 more particularly in the Eutrichid direction. Malacosoma is very 

 peculiar in its neuration, being specialised with regard to the loss of the 

 transverse nervule at the end of the discoidal cell (a peculiarity that it 

 shares with Chond roster/a), while the supplementary basal nervures seem 

 to be somewhat specialised, otherwise the character of the neuration in 

 other respects appears to be generalised, and to call for no special 

 comment. Bacot observes that on larval characters he considers Dyar 

 incorrect in deriving Eutricha from Cosmotriche. Eutricha (as represented 

 by quercifolia) is, he considers, on lajrval characters, more specialised 

 than Dendrolimus (pint) which clearly, in this stage, occupies a position 

 between Eutricha and Cosmotriche, but nearer to the latter. Cosmotriche, 

 he adds, certainly appears to be much more generalised than Eutricha, 



