174 THE CANADIAN ENTOMOLOGIST. 



many other insects. When Milk-weeds are past bloom these Argynnids 

 visit Cnicus pumihim or low Pasture-thistle, and other species. Later on 

 they betake themselves to the gardens, and visit the flowers of Zinnia 

 elega?is and Verbenas. 



In the latitude of Long Island and Northern New Jersey the 

 Asclepiadacecp. flower in the following order : — 



First of all, Asclepias corjiuti, Silk-weed or Common Milk-weed ; then 

 comes A. purpnrascens, or Purple Milk-weed ; next A. tuberosa, or 

 Butterfly-weed ; and finally A. incartiata, the Flesh-colored Asclepias or 

 Swamp Milk-weed. I have found that A. purpurascens and A. incarnata 

 will attract more of Argynnids, Danaids, Hesperids, Macroglossids and 

 Hymenoptera than the other plants mentioned, when two or more species 

 are in bloom at one time. Of these, A. tuberosa, with its orange-colored 

 flowers, can be farthest seen, but comparatively speaking it is not fragrant 

 to our senses, or very faintly so. A. purpurascens, the most fragrant, is 

 much visited by Argynnids and Pamphilas, and after that comes A. incar- 

 7iata. The last is the more plentiful plant, and inhabits swamps and 

 margins of streams. 



It is not an uncommon sight to behold a corymb of either of these 

 Asdepiadacece in the possession of two or three Argynnids, several Skippers 

 and Hymenoptera at one and the same time. All but the Swamp Milk- 

 weed affect a gravelly or poor sandy soil, and may be found along the 

 roadside, on railroad embankments, in fallow fields or skirting sylvan paths. 

 To obtain the sweets from the innermost recesses of the five-lobed corolla, 

 the lepidopterous insect almost buries its head within the flower. Those 

 with a very long proboscis keep a weather eye open, so to speak, to warn 

 them of approaching danger. This nectar must exert an almost intoxi, 

 eating effect on the insectiferous sense, else Argynnids would not suffer 

 one to approach them so closely while extracting honey from the nectar- 

 iferous glands. The flowers of A. cor?iuti have longer pedicels than any 

 other species, and the umbels do not present so compact a head of flowers 

 as in the other mentioned species This drooping of flowers may be of 

 disadvantage to diurnals with long probosces, and is, I believe, a good 

 reason why Argynnids prefer to explore the more upright-standing flowers 

 of other Asclepiads. The flower of A. cornuti, or Milk-weed, is not 

 brilliant, a greenish-white delicately tinted with purple, but emitting a 

 powerful fragrance. Although the larva of Danais archippus feeds on the 

 leaves of ^. corfmti, yet the imago takes its food very seldom from this 

 flower, vyh^n other species are conveniently near. 



