OF NORTH AMERICA. 85 



under the dead bark of a cottonwood tree. These were placed in a 

 bo.K, and kept well supplied with food for a couple of weeks, but they 

 declined to eat, and remained huddled up in the shadiest corner of the 

 box, retaining this position, almost without change, until the middle 

 of August, a period of over three months, in the height of summer 

 without food. The entire lot then assumed the chrysalis state within a 

 few days, some few without spinning any cocoons. The remainder, as 

 though almost all the moisture in the body had been eliminated during 

 their long fast, wove merely a very thin open white web, dotted with 

 minute glistening white beads, like small dew drops, and entirely free 

 from the hairs of the body, which in Halesidota are incorporated into 

 the cocoon. Their peculiar aestivation, seems also to affect the final 

 transformations, as the larva skin retains its shape after the exclusion 

 of the chrysalis, with the exception of the slit on the back of the head 

 and first and second segments, through which the chrysalis escapes. 

 The latter is seldom more than half extruded from the larva skin. This 

 remarkable aestivation has been observed in all the larvae we have raised, 

 (and while these have been numerous, I have never taken an imago 

 at large) and was first pointed out to me by Mr. H. Edwards; who also 

 called my attention to the color of the last pellet of excrement passed 

 by the larva. This is reddish, and appears to be the inspissated 

 equivalent of the drop of fluid usually passed by the imago, soon after 

 its exclusion from the chrysalis. Out often imagines evolved from this 

 batch of larvae, not one of them passed anything before they were killed, 

 thus proving how complete is the elimination of all extraneous matter 

 from the intestines during the larval existence. 



This insect approaches A. atdcea, Hiibner, from Mexico, very closely, 

 if it be not the same thing, in which latter case Ecpantheria incarnata, 

 Walker, should be added as a synonym. The descriptions of these 

 two species agree with that of A. pida, except in the color of the spots 

 on the underside of the primaries, which are said to be red in the two 

 former species, v/hile in a long series of A. pida 1 have never seen 

 them anything but yellowish, or yellowish w'hite. Boisduval (Ann. 

 Soc. Ent. Belg., p. 78, 1868-9,) i^ideed refers to our Californian species 

 as E. aulcea, Hiibn., stating that he has also received the same from 

 Mexico. While strongly of the belief that these will all prove to be 

 descriptions of the same species, it did not seem advisable in the 

 absence of Geyer's figure for comparison, to run the risk of introducing 

 confusion into the synonymy, and for that reason Packard's name is 



