1896.] NATURAL SCIENCES OF PHILADELPHIA. 



The yellow bug Phymata fasciata Gray, 

 abounds on the Verbesina ; on September 28th, 

 I found one which had caught a P. verbesince. 

 This Phymata not only preys on bees, but the 

 butterfly, Lycama exilis, the house fly, Musca 

 domestica, and doubtless many other insects. 

 Another enemy of bees which is found on Ver- 

 besina is a Thomisid spider ; on September 

 22d, I found one of these had caught a P. 

 verbesinw. 



There are various other Verbesma bees, in- 

 cluding the pretty Agapostemon melliventris, 

 which also appears in the spring, then visiting 

 Sisymbrium and Streptanthus. 



(23). BiDENs ARisTOSA (Michx) Britt., (= Core- 

 opsis ARiSTOSA Michx). Mr. Robertson cites 

 this as visited by P. octomaculata. 



39 



tlG. 5. 



(24). Senecio douglasii DC. On this Professor Wooton found 

 P. senecionis, as also an Anclrena and other bees. 



(25). Pectis papposa Gray. This is visited by P. pedidis, but 

 cladothricis, fallax and biparticepshave also been taken on it, 

 while once only a luteola was seen in the net after sweeping 

 Pectis. The flowers are frequented by an ant, Dorymyrmex 

 pyramicus Rog. (det. Andre). One also finds upon them 

 Panurgus (commonly) and Epeolus (rarely), as well as sun- 

 dry Philanthidpe and Bombyliidae, etc. 



The genus Pectis has many neotropical species, extending 

 even south to the Argentine Republic. It has also AVest 

 Indian representatives in Cuba, San Domingo and Cura9oa. 



In reviewing the above list of plants, it will be readily seen that 

 Perdita does not usually frequent the boreal types of flowers, but 

 rather those which extend northward from the neotropical region. 

 This, taken with the known distribution of the genus, strongly sug- 

 gests that in the main we have to do with an austral series of types, 

 which have spread northward and become largely differentiated 

 into species since the glacial epoch. P. octomaculata, however, 

 must be looked upon as a survival from preglacial times ; and 

 here it is especially significant that affinis and senecionis, which 

 more especially represent octomaculata in the west, are the very ones 

 which visit boreal flowers, Solidago and Seneeio to wit. Further, 

 bakerm which does indeed visit Solidago also, shows every indication 

 of being a recent derivative from the Cleome type zebrata ; an in- 



