HARDWICKE'S S C lEN CE-GOS S IP. 



53 



leucophearia (Spring-usher), the wings of the male 

 are long and i ather narrow, while those of the female 

 are scarcely perceptible. In the Scarce Umber {H. 

 aurantiana), which appears in October, the wings of 

 the male are. very large, while those of the female are 

 mere stumps : the body is larger than in either of 

 the others. In another species, the Dotted Border 

 {R. progemmarla), which appears in February, while 

 the wings of the male are large, those of the female 

 are too small for the purposes of flight, but more 

 ample than any other of this degraded, i.e. imper- 

 fectly developed, group. Another Hybernia, H. de- 

 foliaria (Mottled Umbei"), which appears in October, 

 has, as regards the male, lai'ge wings, but the nearly 

 wingless female looks, when on the trunks of trees, 

 like a spider; and the deception is the greater, owing 

 to the length of her legs, and the markings on the 

 body. In Anisoptenjx (escularia (Marsh Moth) 

 wings are quite wanting to the female, while those 

 of the male are ample. In that destructive pest to 

 plantations and orchards, Chimatohia hrumata (the 

 Winter Moth), thousands of which may sometimes 

 be met with at this time of year, the wings of the 

 female are too shoi-t for flight. In places where 

 they abound, the females may be seen crawling 

 like spiders over the tree trunks, while the males 

 flit easily about. 



Another group of the Geometers noted for their 

 robustness and the strong character of their wings, 

 contains three species in which the females are apte- 

 rous. These are the Brindled Beauty [Thigalia 

 pilosaria), the Belted Beauty {Nyssia zoiiaria), and 

 the small Brindled Beauty (iV. hlspidaria). This is 

 the more remarkable because in this family there are 

 only three other species, Bistoii hirfaria, Amphyda- 

 sis prodromaria, and A. betularia, in all of which, 

 strange to say, the females have a larger expanse of 

 wing than the males. 



There is one more group of moths in which the 

 females are more degraded than any of the examples 

 already given; in fact, it has been remarked of them 

 that they are simply egg-sacs, while the males are 

 pretty lively moths. They have seriously been the 

 subject of much difference of opinion as to what 

 group of moths they should be classed with, some 

 at one time leaving them with the Bombycida, and 

 others with the TinecE. They are known by the name 

 of the Psycldda;, and are remarkal)le from the habits 

 of the caterpillars, which form for themselves a case, 

 somewhat similar to that constructed by the caddis- 

 worm, composed of pieces of bark, leaf, or some simi- 

 lar material, fastened together by a kind of glue or 

 silken substance secreted by the caterpillars. When 

 engaged in eating, they protrude a portion of the fore 

 part of the body from the case, and, as they increase 

 in size, enlarge the case by first slitting it, and then 

 letting it out by the addition of more material. 

 Before moulting or changing to a chrysalis, the 

 mouth of the case is closed, and in the latter state 



it serves the purpose of a cocoon. When the final 

 change takes place the male escapes, but the female 

 of one, Fumea gemella, crawls out, in appearance like 

 a little worm, and, after depositing her eggs in the 

 case, dies. Others, like Psyche gmminella, if females, 

 do not emerge from the case, but deposit their eggs 

 within, die, and shrivel up. The young larvse com- 

 mence their experience of life by eating up their 

 dead motiier's body, as rank a case of cannibalism 

 as one could wish for, being, to say the least, an 

 unnatural proceeding. Some of the female Psychidse 

 are not only wingless, but almost footless, without 

 antenna, and have eyes without facets. 



Two or three questions naturally arise as to why 

 the females should be so diff"erent from the males. 

 Is there any perceptible difference in the caterpillars 

 to account for the difference in the moth? Are there 

 analogous cases among other insects ? To the first 

 question no satisfactory answer can, at present, be 

 given. Those who have experimented upon moths 

 and butterflies know that alternations of scanty and 

 bountiful food, or keeping them on scanty food only, 

 tends to produce dwarfs and monstrosities, and that, 

 keeping chrysalides rather dry, or exposing escaping 

 moths and butterflies to the action of dry heat, pre- 

 vents the unfolding of the wings. These things, 

 however, take place with males and females alike, 

 and no such conditions can possibly exist in nature 

 and always produce wingless females. Again, 

 granted it is hereditary, why should it be confined 

 to the female line ? 



To the second question we reply, that although 

 some have fancied that a difference can be detected 

 between the caterpillars which will produce males 

 and those which will produce females, we believe it 

 is, after all, mere fancy, and that, whether there is 

 any essential difference existing either in the eggs 

 or the larva, it is at present one of the unexplained 

 mysteries. 



To the third question an answer in the affirmative 

 can be given. Nut alone among the Lepidoptera are 

 there wingless females. One of the most striking 

 examples is the cochineal insect, in which, while 

 the males possess wings, the females are not only 

 destitute of wings, but almost of limbs : the absence 

 of wings is also seen in the summer or immature 

 females of the aphides. Some species of " walking 

 sticks " supply wingless females ; among the cock- 

 roaches the wings are sometimes wanting in the 

 females, while in the parasite Sirepsipfera, the fe- 

 males arc not only destitute of wings, but were for 

 a long time, from their worm-like appearance, mis- 

 taken for larvaj, till dissection showed that these 

 worm-like creatures were full of eggs. But perhaps 

 the best-known example is the Glow-worm, the fe- 

 males of which alo/ie are luminous, and present the 

 appearance of flat greyish brown larvfe, quite des- 

 titute of wings, while the males are active and fly 

 well. 



