EUPLOEINAE: ANOSIA PLEXIPPUS. 747 



1871, that Mr, Saunders had bred an ichneumon from it, but nothing 

 more is known of it. Mr. C. P. Gillette, however, has bred a Pteroma- 

 lus, P. archippi (Can. ent., xx : 133) in considerable numbers, over fifty- 

 having been reared from a single pupa. They emerged from the same on 

 September 13. From eggs sent me from West Virginia by Mr. Edwards, 

 I reared several specimens of Trichogramma intermedium (89:8); und 

 finally, to round out the forms of })arasitisni, Dr. liiley years ago found 

 a dipterous parasite (Mascicera archippivora (89: 18) iu the larva, which 

 sometimes is so persistent in its attacks that not one caterpillar in fifty is 

 free from it. 



Desiderata. Although this interesting butterfly is one of our best 

 known species, there are several points in dispute regarding it, and many 

 features in its history which need further investigation. The movements 

 of the butterfly in the spring and in the autumn will require systematic 

 and concerted observation over a wide extent of territory before their satis- 

 factory solution can be expected. Where swarms and bevies occur, they 

 should be carefully observed from day to day, and hour to hour, to study 

 the movements and intent of the throng. The whole question of the regu- 

 lar or irregular migration of butterflies can be studied better with this spe- 

 cies than with any other in the world, because there is none so subject to 

 congregational movements which is found where so many intelligent ob- 

 servers are stationed. If, as I believe, there is over the entire extent of 

 the country inhabited by it, at least east of the Rocky Mountains and 

 north of the Gulf States, a periodic movement of the butterfly, to the 

 south in the season which corresponds to the end of September in New 

 England, and to the north in the time of the first (and in the middle belt 

 of the second) season of egg laying, then observers ought to note at these 

 periods the general direction of movement — not over a few feet or rods, 

 but as far as the eye can follow them — of as many specimens as possible, 

 tabulate them and publish the results. By this means I believe a periodic 

 movement could finally be as well established as the annual migrations 

 of birds ; to this work every one can contribute who knows the butterfly 

 by sight. 



Then we need many more careful observations on the immunity sup- 

 posed to be enjoyed by this butterfly in its vai'ious stages — an immunity 

 certainly not perfect, and the exact nature and extent of which will reward 

 only patient and conscientious field work. It would be interesting to know 

 the comparative willingness with which insectivorous birds would devour 

 the caterpillar and that of Papilio polyxenes, which bears some resem- 

 blance to it. The life history, and particularly the number of broods in a 

 season, should be worked out independently in many places, and for sev- 

 eral seasons in each, to detei'mine questions in which writers are at 

 variance. For this the condition and abundance of the butterfly should 



