1966] 
Carpenter — Protorthoptera and Orthoptera 
49 
lacunae received no tracheae. Eventually, the epidermal cells lining 
the lacunae, including those without tracheae, secreted the cuticular 
materials which finally formed the veins. The obvious conclusion 
from this investigation was that the tracheae did not determine the 
positions of the veins. What Comstock and Needham had observed 
was the entrance of the tracheae into the wing pad, followed by vein 
formation, which ultimately closely resembled the tracheal pattern. 
What they did not see was that the blood lacunae, along which the 
veins would form, were already blocked out, before the development 
and extension of the tracheae. 
Holdsworth’s conclusions have been corroborated by the investiga- 
tions of Henke (1953) and of Leston (1962) on the inter-relation- 
ships of veins and tracheae, demonstrating that the lacunae in wing 
pads are the precursors of veins, the tracheae merely occupying the 
available lacunae. Smart (1961) has shown that the cutting of the 
main tracheae in the wing pad of P eriplaneta resulted in degeneration 
of tracheal branches and in retracheation but with an abnormal pat- 
tern, which, however, had no effect on the normal venational pattern. 
His conclusion was that the pattern of tracheation of the nymphal or 
the pupal wing could not be taken as fundamental in determining the 
homologies of the veins. 4 As the situation now stands, the Comstock- 
Needham method of determining homologies of veins, which domi- 
nated investigations of wings for the first half of the present century, 
must be regarded as a side issue which actually led nowhere. How- 
ever, it must also be emphasized that many of the conclusions reached 
by Comstock and Needham, not involving their ontogenetic method, 
are perfectly valid. 
Another approach to the problem of homologies was introduced 
by Lameere in 1923, as a result of his extended and important studies 
on the Carboniferous insects of Commentry, France. Impressed by 
the regularity of the convexities and concavities, he concluded that 
there were originally two media veins and two cubitus veins, 
one of each being convex ( + ) and the other concave ( — ) ; these 
he termed the media anterior (MA), media posterior (MP), cubitus 
anterior (CUA) and cubitus posterior (CUP). He believed that 
some insects had both convex and concave elements, while others 
had various combinations of one or the other. Support) for his con- 
4 I have given this detailed summary of the Comstock-Needham method of 
determining wing homologies because their conclusions, based on this tech- 
nique, have become firmly implanted in American entomological literature 
and in current texts. See, for example, the 1963 edition of Borror and 
DeLong’s “An Introduction to the Study of Insects.” 
