74 SUMMARY OF CURRENT RESEARCHES RELATING TO 



By a further change the whole elevation is covered by an uninterrupted 

 pigmented lamella, as in many butterflies. These pigmented elevations 

 may be thick or sparse, hair-like or simply pointed, and so on. Some 

 reference is made in this connection to fossil caterpillars. 



Morphology of Insects' Wings.* — Herr N. Cholodkovsky commences 

 by stating that, notwithstanding all the text-book statements to the con- 

 trary, the first ring of the thorax of Lepidoptera is in no way connected 

 with the second. At the boundary between its notum and pleuron there 

 is, on either side, a hollow evagination of the chitiuized skin, which is, 

 in an uninjured specimen, closely covered by hairs and scales. In posi- 

 tion and form this outpushing is exactly like the rudiment of a wing, and 

 it would hardly be wrong to call it the rudimentary jjrothoracic wing. Not 

 only has the author observed these rudiments in various Lepidoptera of all 

 the most important families, but Fritz Miiller has seen them in some 

 Termite-larvfe ; Woodward Las described a fossil (Lithomantis carhonaria) 

 with two wing-like appendages to its prothorax, and Grabcr has discussed 

 the matter. 



The pliysiological significance of these appendages is very difficult to 

 understand, but it is important to observe that there are no indications of 

 them in the larva (of Vanessa urticse, at any rate). The wings were pro- 

 bably preceded by api^endages on all segments of the body, and these 

 probably had a resjuratory function in those terrestrial insects from which 

 probably all forms, whether now aquatic or terrestrial, have been derived. 



With regard to this communication, it is j)ointed out by Dr. E. Haase f 

 that the structures now discovered were seen in 1822 by Chabrier in 

 Maeroglossa stellatarum, that Kirby and Spence distinguished them as the 

 prothoracic " tippets " (patagia), from the mesothoracic wing-covers (te- 

 gulee) ; Burmeister and Westwood have also mentioned them. In 1870 

 Speyer gave a detailed account of them, and pointed out that though they 

 were found only among the Lepidoptera, they could not be regarded as 

 characteristic inasmuch as they varied so much in difierent members of 

 the order. They are not to be regarded as anything more than secondary 

 dermal folds, thickly scaled on their upi)er surface only. They may 

 have their homologues in the accessory dermal folds of the Diptera, 

 and the patagia-like structures which are found on the prothorax of some 

 Hymenoptera. 



Colour of Pupae.J — The cause of the relation of pupal colour to that 

 of the surface on which the larval skin is shed, is the subject of exjjeri- 

 meuts by Mr. E. B. I'oulton, who confirms Mr. T. Woods' results. 



The metallic colour common to the pupae of the Vanessidfe can be con- 

 trolled b}' choosing aj^propriate surroundings for the larva before pupation ; 

 a gilt surface rendering the colour more metallic ; a black almost does 

 away with it. The author finds that the colour corresponds with the 

 length of time the larva has been on such a surface before pupation, and 

 that it acts before the moult ; the colour aifects neither ocelli nor the 

 sensitive si)ines exclusively. Experiments were made with an apparatus by 

 means of which the larvje could be suspended partly over a black and 

 partly over a metallic surface, and the author concludes that there is either 

 some terminal organ in the skin, which is affected by the surrounding 

 colour, or that the colour acts directly on some sujierficial element in the 

 larval tissues without the intermediation of the nervous system. 



* Zool. Anzcig., ix. (1886) pp. 615-8. f Turn, cit., pp. 711-3. 



X Trans. Eutom. Soc. Lond., 1886, pp. xlvi.-xlviii. 



