THE EUROPEAK OBSYIAS. 169 



The European Orgyias : Their Specialisation in Habits and 



Structure (in'tli plate><). 

 By T. A. CHAPMAN, M.D., F.E.S. 



Having been fortunate enough to have observed something of the 

 most specialised European speciesof thegenus Orm/ia, viz,,0.auroliinbata 

 and (>. (hthia var. splcndida, and knowing something of the commoner 

 northern species, < Kanti(jiia and O. ffonosti(jiiia, a review of the European 

 species, as regards their specialisation, seems just possible. Unfor- 

 tunately, I have no direct acquaintance with the remaining European 

 species. These, so far as I am able to understand them, are very 

 probably all one species, with a good deal of variation, as regards the 

 formation of local races, and, at any rate, they are vei'y close to one 

 another in habits, if not identical. Staudinger (1901) still presents 

 them as three species, viz., ericae, tn'notephras, and rupestris, but in 

 such a way as to show that he rather does so in deference to tradition 

 than as an expression of his real opinion. 



We are all supposed to be familiar with 0. antiqna. It makes its 

 cocoon in some hollow or crack of tree or stone, in such a way that 

 what I will call the outer cocoon is stretched as a tolerably level, 

 smooth, surface across the hollow, and beneath this is the true inner 

 cocoon, as a matter of fact the outer and inner cocoon are not very 

 definitely separable in many cases ; I ought to say that this is the 

 female cocoon, that of the male is much less specialised and has rarely 

 an outer smooth face like that of the female. On this smooth face the 

 female imago passes all her existence till she has laid all her eggs, 

 with greater or less regularity, as a layer over its surface. (). antiqna 

 may have several broods in a year, and, apparently, always does so in 

 the South of France and the warmer areas of its range, but it always 

 hibernates as an egg. 



The female oi O. antiqna is structurally the least specialised of the 

 genus {i.e., of the five or more European species). Her wings are very 

 small, but her legs and antennip can hardly be said to differ very 

 materially from those of an ordinary winged female. Though she 

 cannot fly, still she is able to walk if she chose to do so ; we may, 

 therefore, suppose that, if not her structure then, her instincts are so 

 far specialised that she only uses her feet for retaining hold of her 

 cocoon and for the necessary movements for properly placing her egg, 

 but never makes any attempt to leave the cocoon. 



My own personal acquaintance with (hyyia (/onontijima is of such 

 ancient date, and was of so perfunctory a character, that I should be 

 more honest to say I really know nothing definite about it. It luckily 

 happens that Mr. ]jacot, and especially the Rev. C. R. N. Burrows, 

 have been able to give me fiiirly full details as to its habits in spinning 

 its cocoon, emerging, pairing and egg-laying. The idea, generally held, 

 is that the habits of <K tj(niasti(iiiia are very similar to those of <>. 

 antiqna, for instance, we find in Barrett that the eggs are laid closely 

 together side by side, on the cocoon, the only difference one notes in 

 the account given being that O. i/onostiijiiia covers tbem carefully with 

 her " scales." This is practically the same as the accounts given us of 

 the American species U. lencastiipua and O. dejinita. O. (lonostitinia, 

 however, in a detail or two of considerable importance, is not thus 

 correctly described. The reason for the errors of observation being 

 July' 1st, 1903, 



