Packard.] 
500 
[Feb. 19, 
Trichoptera, or from forms allied to that group. We should, how- 
ever, prefer the view that the Lepidoptera and Trichoptera had 
a common origin, from some earlier, extinct group. The similarity 
of the imagines of certain of the lower Tineidse and certain of 
the smaller Trichoptera is certainly very marked, the most signifi- 
cant feature being the fact that the mandibles in the two groups 
are either absent, or minute and rudimentary. 
We have attempted, however , 1 to show that the larvae of the 
Panorpidae, judging from Brauer’s figures and descriptions, are 
much nearer in shape and ornamentation to caterpillars than to 
case-worms. Hence, it seems to us probable that the ancestral 
or stem -form of the Lepidoptera was probably a now extinct group, 
somewhat intermediate between the Mecaptera (Panorpidae) and 
the Trichoptera. 
The primitive caterpillar . — We would suggest that the earliest 
type of Lepidopterous larva was allied to some Tineid which lived 
not only on land but on low herbage, not being a miner or sack- 
bearer, as these are evidently secondary adaptive forms. It is ev- 
ident, when we take into account the remarkable changes in form 
of certain mining Tineid larvae described and figured by Chambers 2 
and by Dimmock , 3 that the flattened, footless, or nearly apodous 
mining larvae of the earlier stages are the result of adaptation to 
their burrowing habits. The generalized or primitive form of the 
first caterpillar was, then, like that of Tineid larvae in general, and 
was an external feeder, rather than a miner. The body of this fore- 
runner or ancestor of our present caterpillars (which may have 
lived late in carboniferous times, just before the appearance of flow- 
ering plants and deciduous trees), was most probably cylindrical, 
long, and slender. Like the Panorpid larvae, the thoracic and ab- 
dominal legs had already become differentiated, and it differed from 
the larvae of Panorpids in the plantae of the abdominal legs being 
provided with perhaps two pairs of crochets, thus adapting them 
for creeping with security over the surface of leaves, and along 
twigs and branches. The prothoracic or cervical shield was present, 
as this is apparently a primitive feature, often reappearing in the 
^hird Report U. S. Entomological Commission. Genealogy of the Hexapoda, pp. 
297-299, 1883. Also American Naturalist, Sept., 1883, 932-945. 
2 American Entomologist, in, 1880, 255-262; Psyche, n, 81, 137-227; III, 63, 135, 147; 
iv, 71. Refers to the larvae of the “ Gracilaridae ” and “ Lithocolletidae ” together with 
Phyllocnistis. 
spsyche, in, Aug., 1880, 99-103. 
