128 Psyche [August 
a pupa, but similarly situated; they are quite symmetrical and are 
developed just under the heavily-chitinized tergites which they 
reflex a little. The buds of the metathorax representing the wings 
are slightly larger than the elytral buds; in one specimen they are 
almost entirely covered with brown chitin, in the other the buds 
of the metathorax are largely of a whitish color and their bases 
show through the tergite as white subcircular areas. 
Prothetely has been noted by a number of observers: Heymons 
(1896)! found it in the larva of Tenebrio molitor; Busck (1897)? 
observed it in six larve of Anthrenus varius; Riley (1908)? speaks 
of a prothetelous larva of a pyrochroid beetle, Dendroides canadensis. 
In lepidopterous larvee Hagen (1872) and others mention the silk- 
worm, Bombyx mori, and Kolbe (1903)> the Lasiocampid, Den- 
drolimus pint. 
As aforesaid, prothetely appears to occur most frequently in the 
Coleoptera, and Riley * offers as an explanation of this, the fact 
that the wing rudiment in most coleopterous larve is according to 
Tower ‘not sharply marked off from the body hypodermis and 
is usually directly evaginated to form the imaginal organ.’ The 
step from this condition to an external wing-pad would be com- 
paratively simple, which would not be the case in the Lepidoptera 
and the Diptera for example, for here the wing rudiment is well 
differentiated from the body hypodermis, for the former is in- 
vaginated and thus lies in the body cavity, a condition designated 
by Tower as the “enclosed type” of wing development. 
Inasmuch as all the cases of prothetely noted occur only in 
larve kept under artificial conditions, this accelerated develop- 
ment is probably due in some way to these unnatural conditions. 
Strickland (1911)§, is of the opinion that prothetely “is usually 
caused by keeping larve at an abnormally high temperature. 
This probably results in an increased supply of the enzymes which 
cause these histoblasts to develop.” 
Neither larva of Photuris pennsylvanica pupated; they lagged 
behind the other larve, being, so to speak, already partly in the 
1 Heymons, R., 1896, Sitzungber. d. Ges. nat. Fr. Berlin, pp. 142-144. 
2 Busck, Aug., 1897, Proc. Ent. Soc. Wash., (V, p. 123. 
3Riley, Wm. A., 1908, Ent. News, XIX, pp. 136-139. 
4 Hagen, H. A., 1872, Stettin. ent. Ztg., pp. 392-393. 
5 Kolbe, H. J., 1903, Allgem. Zeitsch. fiir Ent., Bull. 8, No. 1, p. 28. 
6 Strickland, E. H., 1911, Biol. Bull., X XI, pp. 313-327. 
