THE ENTOMOLOGIST. 113 
character, is said by all observers to be similar to that of 
Catocala, Drasteria, and other Heterocera, viz., deflexed or 
incumbent. Yucce, both in manner of repose, in colour, and 
in pattern, is a staunch Hesperian. 
In short, a careful consideration of the characters of our 
yucca borer shows that in all the more important characters 
it is essentially Hesperian; and that in most of those characters 
by which it differs from the more typical species of that family 
—as in the small spurs, in having only the apical ones on the 
hind tibia, in the bial spines, and difference in size of legs 
' —it is more Rhopalocerous than Heterocerous. The same 
holds true when we consider the adolescent states. In the 
small head of both larva and imago, and in the very large 
abdomen, it is abnormal; but these characters are traceable 
to the abnormal larval habit, and are very unimportant 
compared to the pterogostic and other characters cited. | 
have long since concluded that general larval form and 
appearance is so dependent on habit and so variable according 
to habit, that it is less valuable than more minute structural 
characters, and that for purposes of classification it has even 
less value than egg-structure, and infinitely less than imaginal 
characters. All endophytous Lepidopterous larvae, of what- 
ever family, have certain general resemblances that are a 
consequence of similarity of habit; and I give it as my 
emphatic opinion that Yucce is a large-bodied Hesperian, 
which, though approaching the Castnians through Synemon, 
has no real relation with them. In certain marked characters 
it departs from the Hesperians as at present understood, and 
the only question which a careful study of the species gives 
rise to in my mind is—not whether it should be considered a 
Castnian, but whether it offers characters that necessarily 
separate it from the Hesperians. Families should, I think, 
be made as comprehensive as possible and not unduly 
multiplied ; and in considering aberrant forms, the objects of 
classification are best subserved by retaining them in what- 
ever division can claim the balance of characters. It is better 
to widen than to restrict in the higher groups. LeConte does 
better service in bringing Platypsylla among the Coleoptera 
than does Westwood in creating a new Order—Achreioptera 
—for it. Phylloxera, in Homoptera, is much more wisely 
retained in the Aphididae than made the type of a new Family. 
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