BEES 199 



discolor) are great favorites of vernal species of Andrena, whence 

 Smith calls them " harbingers of spring." The pussy-willows bloom in 

 northern New England during the latter part of April, and their bright 

 yellow aments are very pleasing objects in the cold gray landscape. 

 They are very attractive to a varied company of insects, as honey-bees, 

 bumblebees, flies, butterflies and beetles. It is a busy scene and one 

 which the naturalist can never tire of watching; but it is not one of 

 unmixed happiness, for little tragedies take place before our eyes. 

 Among those which come to sip the nectar are little dance-flies (Empi- 

 didaa), and not infrequently they are seized and carried away bodily by 

 black robber ants, which roam everywhere. Honey-bees and many 

 species of Andrena come in great numbers to procure pollen for brood- 

 rearing. A part of the Andrenid bees gather only a portion of the pollen 

 they require from the willows and the balance from the maples, plums, 

 cornels and Viburnums ; but there are four species (A. illinoiensis, A. 

 marice, A. erythrogaster and A. moesta), which get their whole supply 

 from this genus of plants. Of the autumnal flying species of Andrena 

 there are five (A. canadensis, A. nubecula, A. solidaginis, A. hirticincta 

 and A. asteris), which I have collected only on the flowers of the Com- 

 positas, or aster family; and four of these bees confine their visits very 

 largely to the golden-rods. In both Salix and Solidago the inflorescence 

 offers an ample supply of nectar and pollen and there is little tempta- 

 tion for Andrenid bees to go elsewhere, when their time of flight coin- 

 cides with the period of blooming of these two genera. 



But in other localities Andrena erigenice is reported to be a mono- 

 tropic visitor of the spring beauty (Claytonia virginica), Andrena violce 

 of the violet (Viola cucullata), Andrena geranii maculata of the wild 

 geranium (Geranium maculatum), Andrena fragariana of the straw- 

 berry (Frag aria virginica) and Andrena parnassice of Parnassia caro- 

 liniana. It is not so easy to explain the behavior of these latter bees. 

 It seems very remarkable that they should restrict their visits so closely 

 to the flowers mentioned. 



Macropis ciliata, or the loosestrife bee, usually gets its pollen from 

 the flowers of the common loosestrife (Lysimachia vulgaris) ; while 

 many species of Panurginus are taken only on the inflorescence of the 

 Composita?. 



But this habit of visiting only one kind of flower is perhaps better 

 illustrated by Perdita than by any other genus of bees. Only one 

 species of Perdita is found in Maine ; but in the western states some 90 

 species occur, of which about forty live in the arid regions of New 

 Mexico. In Maine Perdita octomaculata is found almost exclusively 

 on the panicles of Solidago juncea, the earliest blooming of the golden- 

 rods; and I have never met with it on any other species except in one 

 instance. In New Mexico two species of Perdita are found on the wil- 

 lows, Perdita zebrata visits only Cleome serrulata, Perdita crotonis 



