1I3S (Juiir. 



iiiouicnt the Ctiterpillar's skin is cast iind the chrysalis revealed the 

 bundles of minute tracheae are torn out. In the chrysalis large tracheae 

 are found in the imperfect wings, but these subsequently disappear, 

 and it would seem that no tracheal system can be found in the com- 

 pleted wing. The changes that go on in the wings when the butterfly 

 emerges are very great, and the limp sacs become converted into 

 the rigid sheet-like structures covered with scales. The scales are, 

 however, formed long anterior to the emergence of the butterfly, 

 before, in fact, the wing-skin on which they are subsequently implanted 

 exists. The origin and development of the wing-nervures is obscure 

 and a subject of great difficulty. It has been remarked that tracheae 

 exist in the wings of the chrysalis, where they have much the same 

 arrangement that the wing-nervures have in the perfect insect. Hence 

 it appears to be commonly supposed that the tracheae are changed into 

 the nervures ; this, however, appears not to be the case. It seems 

 probable that the real origin of the structures that Lepidopterists 

 now consider of so great importance in the classification of the objects 

 of their study, is from string-like structures which run near the 

 tracheae, called Semper's rods. The tracheae ultimately disappear ; 

 their propinquity with Semper's rods seem to indicate that they take 

 some share in the formation of the nervures ; ultimately the remains 

 of Semper's rods may be found in the interior of the nervures. 



When the wing is completed the sides of the bag from which it 

 was formed become adherent by dried matter with a somewhat pillar- 

 like arrangement, this is apparently refuse material from which has 

 been extracted and withdrawn into the interior of the insect's body 

 all the material that may be of further use to the winged insect. 



Cambridge: Mat/, 1896. 



Qastropacha iUcifoHa on Cannock Chase.— On May 17th, when collecting on 

 Cannock Chase with Mr. Basil Burnett, I had the good fortune to find a fine male 

 Ga'^tropacha ilicifolia. This is almost a re-discovery, as the insect has not been 

 taken here for U or 15 years. It was found some distance from its old haunts, but 

 its exact locale will remain a secret for the present in the interests of the insect as 

 well as myself. I hope with the clue so obtained to get some larvis this year.— 

 Richard Frekr, Rugcley: May \Sth, 1890. 



yote on. LeiK-nnia paUens, ab. ectypa, Rh. — On p. 99 (ante) Mr. Barrett 

 rleseribes a form of Leucania pallens, which has red fore-wings, but without the 

 usual white, fine, longitudinal lines, and states that "this rarietr of Leucania 



