12 



HARDWICKE'S SCIEN CE-GO S S IP. 



compose the integument, and is readily separable 

 from the other two, especially if it has been soaked 

 in liquor potassae, or for two or three days in water : 

 it occurs on all parts of the larva, and apparently 

 consists of several closely adherent sheets, or 

 lamina? of structureless tissue. I cannot discern 

 the least appearance of cellular structure in it. 

 Sometimes I have thought I discerned a fibrillated 

 appearance, but think that this is only due to 

 foldings of the laminae. On the dorsal and ventral 

 surfaces these laminae are superimposed evenly one 



Fig-. 7. Larva slightly enlarged. 



3# W 



m^^m^^kWMM Basses*! 



Fig. 8, a. 





I ig- 8, b. 



Fig. 8, 



Fig. 8, d. 



Fig. 8. Integument: a, the outer layer, showing ens largj an! 

 anumberof smallhairs, — theceutral portionsof these (inures 

 represent the lateral bands; b, the intermediate layer; c, 

 the innermost layer ; d, section showing the corrugations 

 of the innermost layer, x 100. 



over another, and the substance of which they are 

 composed having little elasticity, the integument is 

 incapable of being stretched to any material extent. 

 On the lateral bands, however, the laminae are cor- 

 rugated, as shown in the drawing annexed, the lines 

 of corrugation taking generally a longitudinal but 

 somewhat sinuous course parallel to the length 

 of the bands ; the result of which arrangement, 

 coupled with the inequalities of the cuticular layer, 

 is, that the integument of these portions of the 

 larva, though allowing of but little extensibility in 

 a longitudinal direction, can be stretched very con- 

 siderably in the opposite or transverse one, the 

 intermediate layer, of course, yielding like the meshes 



of a net would do in similar circumstances. On the 

 removal of the tension, the integument resumes its 

 original condition. I have frequently noticed the 

 habit the larvae have when handled of shortening 

 and swelling out their bodies, but had no idea, till 

 close examination revealed it, how elaborate was 

 the provision necessary to secure the performance 

 of so apparently simple an act. I should mention 



Fig. 9. The Head and Mouth: tn, the antennae; Ir, the 

 labrum ; mm, the mandibles; mv mx, the maxillae ; ?', the 

 broken edge of the soft integument of the body, all above 

 which is internal ; s, the spur, x 50. 



T7lt 



Fig. 10. Longitudinal and vertical section through the front 

 part of the head, showing Ir, the labrum ; m, the mouth; 

 mt, the serrated mentum ; sd. the salivary duct : mh, the 

 serrated margin of the head beneath the mentum, x 50. 



that the cuticular layer seems to be continued over 

 the horny casing of the head and the mouth-organs, 

 and that beneath it is a considerable thickness of 

 horny substance, in which I cannot detect any 

 structure. I believe it to be a continuation of the 

 laminated layer already described, which here passes 



