160 Transactions. — Zoology. 



smooth round eggs of Bhapsa scotosialis, flat on attached 

 surface, are more primitive than Arctid (Nyctemera) eggs r 

 which are similar in shape but with hexagonal sculpture, or 

 typical Noctucs (Melanchra insignis) eggs, more flattened at 

 the base, with parallel corrugations converging to the centre. 

 Bhopalocera ova have elaborate sculpture (figs. 1, 2). 



The eggs of Lepidoptera most frequently have hexagonal 

 figures raised on the surface ; more highly specialised forms,, 

 with parallel ribs, appear to be derived from the hexagonal by 

 the decadence of the transverse sides of the hexagons and 

 greater development of the longitudinal sides. I have, in 

 fact, examined a Tineid egg which seems to actually illustrate 

 the process. Egg-shells with hexagonal patterns are probably 

 similar in composition to beeswax, recent experiments* having 

 proved the natural formation of "crystalline" hexagons in. 

 the pure beeswax upon which bees build up the cells of 

 honeycomb ; the size of the hexagons has been varied experi- 

 mentally, according to the thickness of the wax, " from those 

 of nearly an inch across to others of microscopic dimen- 

 sions," and a variety of these "crystalline " bodies has been 

 formed by the treatment of certain " waxes with other fats, 

 oils, and waxes." It may be noted that the ovum of Vanessa 

 gonerilla (fig. 1) has an ornamentation which is not hexagonal, 

 and the secretion by which the ovum is attached at its base 

 to the leaf upon which it has been deposited is of irregular 

 "crystalline" formation, but nevertheless largely hexagonal. 

 Certain Tortricid ova look like mere splashes of white, green, 

 or brownish matter, due apparently to a secretion which 

 covers them, which is likewise characterized by " crystalline " 

 hexagons. 



The larvae of Lepidoptera are composed of fourteen bilate- 

 rally symmetrical segments, which comprise the head=l, 

 thorax (pro-, meso-, post-) = 3, abdomen = 10. The head near 

 the mouth has six ocelli on each side. In their imago stage 

 Lepidoptera have compound eyes (except, perhaps, female Psy- 

 chidce) ; near the ocelli in front are antennae, broad and fleshy 

 organs very unlike those of the imago ; at either side of the 

 mouth are the jaws, and below are the maxillae and the 

 labium (lower lip), with its minute palpi and terminal spin- 

 neret, from which the larva produces its silken threads. The 

 thoracic segments have legs which ultimately become the 

 imaginal legs, and certain abdominal segments have fleshy 

 ventral extensions terminated by one or more rows of hooks ; 

 these are termed prolegs (claspers on 10), but Dr. Sharp! has 

 proposed a more appropriate term, "abdominal feet." These 



* C. Dawson, F.G.S., and S. A. Woodhead, in "Natural Science," 

 vol. xv., p. 347. 



f "The Cambridge Natural History," vol. vi. ; Insects (part ii.). 



