Bs 
136 ENTOMOLOGICAL NEWS. [March, ’08 
The Abnormal Appearance of External Wing-buds 
in Larvae of Holometabolous Insects. 
By Wo. A. RILEy, Ithaca, N. Y. 
The literature of entomology abounds in reported instances 
of insectan malformations varying all the way from slight 
abnormalities in venation or in the segments of an antenna, to 
duplication of appendages, or to those striking monstrosities in 
which the head of the larva is preserved by the imago. When 
we consider the minute scrutiny of the systematists it is not 
surprising that the vast majority of these instances relate to 
adult insects. It is to another type of abnormality—the appear- 
ance of external wing-buds in the larval stage—that I wish to 
call attention. 
It is a well known fact that the wings of insects with com- 
plete metamorphosis are developed as internal invaginations 
during the larval stage and normally become visible externally 
only at the time of pupation. So far as I know the recorded 
cases of abnormalities in which the wing-pads are external in 
the larva all relate to two species of Coleoptera.—Tenebrio 
molitor and Anthrenus varius.* 'To these may now be added 
a third, that of the Pyrochroid, Dendroides canadensis Latr. 
In 1896, while experimenting with meal-worms (Tenebrio 
molitor), Heymonst+ found a full-grown larva which possessed 
a pair of peculiar appendages on the meso- and metathorax. 
These appendages were symmetrical, those on the mesothorax 
being somewhat larger than those on the metathorax. Closer 
*T except the remarkable cases, reported by Cesare Majoli, 1813, 
of silk worm larve which, instead of forming cocoons after the fourth 
molt, developed wings and other structures of the adult. From the 
meager accounts available (Stannius ’35, Hagen ’72) it seems to me 
that we here have to do rather with abnormal adults which have pre- 
served larval characteristics. To be sure, the line between the two 
types is rather arbitrary and it is greatly to be hoped that in the fu- 
ture any instances similar to those recorded by Majoli will be carefully 
and fully reported. 
+ Heymons, R. ’96. Filiigelbildung bei der Larve von Tenebrio 
molitor. SB. Ges. naturf., Berlin, 1896, pp. 142-144, Also in Ent. 
Rec. xi, pp. 67-68. 
