338 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
scattered in some diurnal Lepidoptora, but a localized arrangement is 
commoner. They lie on the upper surface of all the wings in Hetero- 
nympha. They often occur on the anterior wings only : — concealed by a 
costal fold in Casyapa , Hecatesia, Aganais, &c. ; on the upper surface in 
Ulysses , Peranthus , Argynnis , &c. ; on the under surface in Bizone and 
Celerena. Often they occur on the posterior wings only : — on the 
anterior margin in Patiila and Argiva ; on the upper surface in Eronia , 
Ideopsis, Banais, Amathusia, Begadia , &c. ; on the abdominal or internal 
area, folded upwards in Ornithopterus pompeus and Papilionidse, folded 
downwards in Morphid® ; on the lower surface in Plecoptera. Moreover 
in many Lepidoptera the parts of the wings which rub against each 
other in flight bear complex combinations of odoriferous scales and hairs. 
But in Cliserocampa the odoriferous organs are thoracic ; in most 
Sphingidse and Agaristidse and in some Noctuidas they are abdominal ; 
in almost all Danaidse and in many others they lie near the genital 
aperture. Finally, the organs may lie on the palps (in Bertula ), or on 
the appendages, as in Ismene , Caprila , Hyblsea, and many others. 
Development of Nervures of Wings of Butterflies.* — Dr. E. Haase 
has made an examination of the development of the neuration of Papilio 
Machaon. He finds that the so-called costa of the forewing is only a 
marginal thickening, but that all the other nervures are formed by 
tracheae. The whole trunk of the latter becomes a concave or a branched 
convex nervure or some branches become convex and others concave 
nervures. The so-called convex folds in the middle cell of the wing 
are the remains of radial and median tracheal trunks, as van Bemmelen 
has already shown for the Nymphaliidae. As in the Trichoptera three 
median trunks become convex nervures, but only the two most anterior 
cubital branches become convex nervures. 
The nervures arise by the thickening of narrow membranous folds 
on each side of the wing over those tracheae which become converted 
into nervures. The tracheae themselves are single, but the cuticular 
structures which fuse into nervures are double. The closure of the 
primitively open wing-cells is effected by purely cuticular thickenings. 
The so-called costa of the hind wing is formed by the fusion of the 
subcostal with the first radial branch. The author is not inclined to 
accept the views of Adolph as to the morphology of the nervures of the 
wings of butterflies. 
Effects of different Temperatures on Pupae of Lepidoptera.t— Mr. 
F. Merrifield has been making experiments on the conspicuous effects on 
the markings and colourings of Lepidoptera caused by exposure of the 
pupae to different temperature conditions. He finds that both the 
marking and the colouring of the perfect insect may be materially 
affected by the temperature to which the pupa is exposed. The 
markings are chiefly affected by long-continued exposure, probably 
previous to the time when the insect begins to go through the stages 
between the central inactive stage and emergence. Colouring is chiefly 
affected during the penultimate pupal stage, that is, before the colouring 
of the imago begins to show. A low temperature during this stage causes 
* Zool. Anzeig., xiv. (1891) pp. 116-7. 
t Trane. Entomol. Soc. Lond., 1891, pp. 155-68 (1 pi.). 
