450 Dr. R. J. Tillyard on 



enormous mass of nerve-cells forming a large Johnston's 

 organ. Young Mecopterous larvae also have the abdominal 

 walking-legs distinctly segmented, like thoracic legs, and 

 the same appears to be true of the first instar of the larva 

 of Micropteryx. As the larva grows older, the abdominal 

 legs become smaller in comparison and lose their segmenta- 

 tion, the larva progressing more and more by means of the 

 wave-like motion of the segments from before backwards, 

 without any actual gripping of the surface by means of the 

 legs. It would seem probable, therefore, that, in the normal 

 Lepidopterous larva we have in the so-called " prolegs," 

 with their circlets of hooks, a specialisation of the basal 

 segment or coxa of the original abdominal walking-leg 

 (or segmented endopodite), homologous with the thoracic 

 leg, but already reduced in the larval forms of the first 

 Ptcrygota. 



While we see, therefore, a definite relationship indicated 

 by the larval type of Sabatinca with that of the Order 

 Mecoptera, we are unable to indicate any such relationship 

 between this same larval type and that of the Trichoptera. 

 The latter has a prominent head, long, cylindrical body, 

 strongly formed thoracic legs, and no abdominal legs at 

 all except the anal pair, which are specialised as gripping- 

 claws or hooks. It is specialised for an aquatic existence, 

 as is also the pupa, v/ith its swimming-hairs and other 

 specialised structures. We can only conclude that Sabatinca 

 exhibits a larval type v/liich is in most points much more 

 archaic than that of the Trichoptera, and one which it 

 would be impossible to derive from any larval type known 

 within that Order. 



Turning next to the pupa, we may note first of all the 

 very general resemblance in the shape of the cocoon and 

 the form of the pupa to those found in the more archaic 

 types within the Order Planipennia; with this difference, 

 that whereas the cocoon of the Planipennia is spun from 

 the anus, it seems practically certain (though not actually 

 observed) that the cocoon of Sabatinca is spun from the 

 salivary glands, though without the aid of a true spinneret. 

 This would account for its coarse, somewhat leathery 

 texture; for the silk would be exuded rather as a stream 

 of glue than as a fine thread. The general form of the 

 pupa is that of the primitive jpwpa libera found throughout 

 the Orders Mecoptera, Megaloptera and Planipennia, and 

 also, with certain specialisations, in the Trichoptera. The 



