138 ENTOMOLOGICAL NEWS. [March, ’08 
dermis and is usually directly evaginated to form the imaginal 
organ.’ ‘Thus it is a comparatively easy step to the abnormal- 
ity of a free, external wing-pad, whereas such a condition would 
be much more abnormal with the enclosed type of the Neurop- 
tera and Lepidoptera or the still more highly specialized 
stalked type characteristic of the higher Diptera. 
Intermediate between the simple and the enclosed types is the 
“recessed type” of Tower (the Corethra type of Gonin). As 
defined by the former, here “the fundament is invaginated and 
then evaginated, and so lies in a hollow niche in the hypoder- 
mal wall, but opens broadly against the cuticula.” This type 
he found in the Scarabzide among the Coleoptera while Weis- 
mann, 66, had reported it for Corethra, Simulium, and other 
nematocerous Diptera. Thus it is possible that specimens of 
these forms may be found in which the buds are free on the 
surface, though no such instances have been reported. 
As to the significance of the monstrosities under considera- 
tion there have been advanced two views. 
According to the one interpretation the occurrence of the 
external wing-pads in the larva is to, be regarded as an in- 
stance of atavism—a harking-back to a period when the larva 
bore wings. 
The second interpretation, that favored by Heymons, is that 
in these cases we have illustration of anticipatory monstrosities.t 
a kind of premature development in which characters normally 
present in the pupal state are present. abnormally in the larva. 
He supports this view by citing other abnormalities present in 
his specimens. 
That the latter interpretation is the correct one is strongly 
supported by Mr. Powell’s specimen. The most striking evi- 
dence is afforded by the fact that in addition to the usual lar- 
This instance and several very striking cases of anticipatory mon- 
strosities in lepidopterous larve (prematurely developed imaginal 
antennae, maxillae, and legs) have been very fully discussed by H. 
J. Kolbe (Allg. Z. f. Ent., 1903, pp. 1-9, 25-30), who proposes for 
the phenomenon the term “prothetaly,” TeAos completion, mpobew to 
run before. 
