﻿OF THE STATE ENTOMOLOGIST. 179 



Castnians through Synemon, has no real relation with them. In certain marked charac- 

 ters it departs from the Hesperians as at present understood, and the only question 

 which a careful study of the species gives rise to in ray 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 classifica- 

 tion are best subserved by retaining them in whatever division can claim the balance of 

 characters. It is better to widen than to restrict in the higher groups. LeConte does 

 better se;;vlce in bringing Platypsylla among the Coleoptera than does West wood in cre- 

 ating a new Order — Achreioptera — for it. Phylloxera, in Ilomoptera, is much more 

 wisely retained in the Aphididie than made the type of a new Family. Let Yuccce, 

 therefore, be retained in Hesperidte. By its aberrant characters it may constitute the 

 type of a third tribe, for which I would propose the name Castnioides. This Tribe con- 

 sists at present, in addition to Megathymus yuccce, of two other good species,* the one 

 from Mexico, the other from Costa Kica. It is very probable that the number will be 

 greatly increased as we become more familiar with the Lepidopterous fauna of Mex- 

 ico and Central America, where the Yuccas and Agaves abound ; for I have little 

 doubt that the last-named plants will also be found to nourish other species of the 

 Tribe. 



ENEMIES. 



I have reared from the Yucca Borer eleven Tachina flies, all belonging to the 

 species which I have designated anonyma, and which infests the larvse of a number of 

 other Lepidoptera.f The fact that Yuccce is attacked by such a parasite is further proof 

 that it is more or less an external feeder, since it is hardly probable that the parent 

 Tachina would enter the burrow, and I know of no genuine endophytes that are simi- 

 larly attacked. 



COXCLUSIOX. 



"Whether we have in our \ ucca Borer a remnant of more ancient and synthetic 

 types from which the Castnians on the one hand and the Hesperians on the other are 

 derived, or whether we have in it a more recent variation from the more typical Hespe- 

 rians, are questions which, with present knowledge, permit only of a speculative an- 

 swer. The former hypothesis is, however, the more plausible. The Castnians, while 

 occurring in Mexico, find their greatest development in Central America and Brazil. 

 The few Castnioides known, inhabit the southern part of North America. During the 

 tertiary period, when the ocean reached over the whole Mexican plateau northward, 

 the fauna of North and South America was much more similar than at the present 

 time. It is not difficult to conceive how a Lepidopterous family that was then common 

 to both divisions of the continent, may since that time have deviated in the two direc- 

 tions indicated, and yet have left some less modified forms in the intermediate 

 country. We are assisted in this conception if we view, with some botanists, the Yuc- 

 cas as remnants of an ancient flora. 



We may learn from the history of this butterfly, as from that of the Hackberry 

 butterflies, J how unsafe it is to describe, and particularly to create genera, from mere 

 drawings. Megaihymus, as founded on Boisduval's figures, is very much of a myth. It 



*^giale Kollari Folder and yE. indecisa Butler and Driice. 

 14tliRep., p. 12!t. 

 ilith Rep., p. 150. 



