On the Antenna and Trophi of Lepidopterous Larvae. 11 



Qracillarim and Ornix leave the mine and continue to feed external- 

 ly; others, as Lithocelletis of the flat group of larvae pass the remain- 

 ing two stages of larval life and the pupa state in the mine, with the 

 labrum and mandibles more degraded, but the other organs more per- 

 fect, but they do not eat. While Phyllocnistis passes its remaining 

 stage in the mine without eating, and with all of its trophi except the 

 spinneret atrophied. Can all this be the result of the influence of 

 external condition ? 



I pass now to a consideration of the separate organs. The Axten- 

 xje consist always in Lepidopterous larvae of a short basal joint, a 

 longer cylindrical one which ends in various minute processes and 

 hairs, one, or sometimes in large larvae two, of which (hairs) are greatly 

 elongated, and are no doubt tactile organs (see figs. 6-12). The 

 number of the terminal processes appears to be normally five, though 

 sometimes I have not been able to detect so man}". The only differ- 

 ences that I have been able to detect in these organs is in the number 

 or size of their terminal processes, and in the relative size of the joints. 

 I find nothing in the antennae of the larvae that can be of an}' practical 

 value in classification, and the uniformity of their structure contrast 

 strongly with the variety presented by the same organs in the imago. 

 In the " first form " the antennae differ from those of the second, as do 

 the trophi (compare figs. 1, 3 and 5 with the others), and are much de- 

 graded. 



In the Labial palpi there is scarcely any difference throughout the 

 order. The}' always consist of an elongate basal joint, with a small 

 hair at its apex by the side of the minute second joint which ends in a 

 longer hair (fig. 14). 



The Labium is large in the "first form" (figs. 16 and 17). In the 

 ordinary form, that which Burmeister calls the shield of the spinneret, 

 seems to me to be the true labium, whilst the labium of Burmeister is 

 rather the mentum, and that which Burmeister calls the spinneret is 

 only a part of that organ, and may be called its sheath or case. The 

 true spinneret, which is a mere prolongation of the united silk glands, 

 is sometimes seen protruding be} T ond the lip of this sheath, fig. 15, "a" 

 spinneret; sheath, which is supported on three arched chitinous 



rods; u c" labium proper, or sheath of Burmeister. This organ (the 

 labium proper) is a simple membrane, elongated and pointed in most 

 of the heterocera, but sometimes shorter, and blunt, or rounded, or 

 emarginate, on its anterior margin, and at its base clasping the sheath 

 and spinneret. The mentum contains a complicated series of mus- 



