446 BRITISH LEPIDOPTERA. 



Pinaridae of Kirby, where, in the genus Suana and its allies, we find 

 species in which the difference is most extreme, e.g., the males may be 

 only Hiii. across the wings, whilst the females may have three times that 

 expanse. The African genus Hilbrides contains imagines, the wings of 

 which are destitute of scales and hence transparent, whilst their slender 

 form resembles that of a butterfly. The amazing power that some of 

 the virgin females have for " assembling " the males is very remark- 

 able, and dozens of males of M. rubi, L. quercus, and P. trifolii are 

 often attracted from great distances by such a female. The males of 

 most of the species are strongly attracted by light, and were it not for 

 this mode of capture (and breeding) many of the imagines would be 

 scarcely known, and this is really the case with L. lancstris and 21. 

 castrensis, the imagines of which have rarely been observed wild in 

 Britain, abundant as the larvae are in many localities. 



Bearing on the question of sexual dimorphism one may here 

 note the prevalence of gynandromorphous forms in this super- 

 family, the difference in the sexes making the examples very con- 

 spicuous and remarkable. These specimens vary greatly in the manner 

 and degree of combination of the sexes in the same individual. The 

 most common form possibly is that in which the whole of one side — 

 antenna, thorax, legs, wings, abdomen, and genitalia — is typically 

 male and the other side female. These examples almost always show 

 a laterally bisexual condition of the genital organs, and it would appear 

 that this modification of the latter is always accompanied by the 

 lateral division in which the insect shows the modification of colour, 

 wing-shape, antenna? and leg-structure, indicating different sexes, on 

 the two sides. It has been said that such insects (if they could be 

 divided longitudinally through the head, thorax, and abdomen) would 

 be cut into a male and female half. To us it seems that the modification 

 of the sexual organs is the primary cause of the secondary sexual appear- 

 ances, and that whenever the organs are modified the secondary sexual 

 characters, as represented by wing-shape, antenna?, colour, &c, follow as 

 a natural response to the stimulus afforded by this modification of the 

 actual sexual organs. The species in which gyandromorphism appears 

 to have been noticed are — Trichiura crataegi, Malacosoma neustria, M. 

 castrensis and var. veneta, M. alpicola, Lachneis lanestris, Macrothylacia 

 rubi, Pachyijastria trifolii var. medicaijinis, Lasiocawpa quercus, L. 

 fasciatella var. excellent, Cosmotriche potatoria, Dendrolimus pini, 

 Eutricha quercifolia and E. populifolia. Tbe known gynandromorphous 

 examples of British species will be dealt with at length later. 



The resemblance of the resting imagines of the Lachneids to 

 dead leaves is almost too well known to need repetition. The peculiar 

 mode by means of which the costa of the forewing of E. quercifolia is 

 made to resemble the midrib of a brown leaf, the veins being represented 

 by the nervures of the forewing on one side and by those of the pro- 

 truding "lappet" of the hindwing on the other, and the almost equally 

 perfect resemblance of a C. potatoria, hanging from a stout grass or sedge 

 culm, to a yellowish leaf, must be known to all, and Barrett records that 

 near Norwich, some years ago, he saw a batch of eggs of L. lanestris on a 

 hawthorn twig, looking particularly velvety and exquisitely arranged, 

 so he picked the spray and had carried it several hundred yards before 

 he discovered that an apparently dry hawthorn leaf drawn closely to 

 the stem just below the eggs, was really the living female moth, still 



