140 HYMENOPTERA. 



Harris' MS. notes, was found in the perfect state in cocoons 

 within earthen cells under stones, April 15th. The cell she con- 

 structs is half an inch long, oval, cylindrical, and contracted 

 slightly into a sort of neck just before the opening for the exit 

 of the bee. From Mr. James Angus I have received the pellets 

 of pollen, about the size of a pea, in which it deposits its eggs ; 

 the larvae were about one-third grown in August. 



This species is larger than Osmia simillima of Smith, while 

 the male antennae are much paler, being fuscous. The front 

 of the head is covered with long dense yellow ochreous hairs. 

 The vertex is not of so dark a green as in 0. simillima , and 

 is covered with coarse punctures. The thorax is heavily clothed 

 with yellow ochreous, thick hairs. The abdomen is yellowish, 

 and much more hairy. The legs are stout, fuscous, with yel- 

 lowish hairs. Length, thirty-five inches. 



Our smallest and most abundant species is the little green 

 Osmia simillima of Smith. It builds its little oval, somewhat 

 urn-shaped cells, against the roof of the large deserted galls of 

 the oak-gall fly (Diplolepis confluentus), placing them, in this 

 instance, eleven in number, in two irregular rows, from which 

 the mature bees issue through a hole in the gall (Plate 4,* Fig. 

 14. From specimens communicated by Mr. F. G. Sanborn). 

 The earthen cells, containing the tough dense cocoons, were 

 arranged irregularly so as to fit the concave vault of the larger 

 gall, which was about two inches in diameter. On emerging 

 from the cell the Osmia cuts out with its powerful jaws an 

 ovate lid, nearly as large as one side of the cell. Both sexes 

 may be found in April and May in the flowers of the willow 



* EXPLANATION or PLATE 4. Fig. 1, a cell of the Humble-bee; natural size, 

 with the pollen mass upon the top. Fig. 2, end view of the same mass, showing 

 the three eggs laid in three divisions of the cavity. Fig. 3, Xylocopa Virginica, the 

 Carpenter Bee. Fig. 4, the larva of Xylocopa Virginica; natural size. Fig. 5, 

 the nest containing the cells of the same, with the partitions and pollen masses, 

 on which the young larva is seen in the act of feeding; natural size. Fig. 6, 

 young larva of Anthrax sinuosa; side view. Fig. 7, pupa of Anthrax sinuosa, 

 side view; natural size. Fig. 8, the Leaf-cutter Bee (Megachile), on a rose leaf, 

 in the act of cutting out a circular piece. Fig. 9, cells of Megachile, in the elder; 

 natural size. Fig. 10, larva of Ceratina dupla, the little green Upholsterer Bee; 

 enlarged. Fig. 11, cells of the same in the stem of the elder; natural size. Fig. 

 12, cells of Osmia lignivora, new species, the wood-devouring Mason-bee, exca- 

 vated in the maple ; natural size. Fig. 13, cells of Osmia simillima, the common 

 green Mason-bee, built in the deserted gall of the Oak-gall Fly. Fig. 14, a single 

 earthen cell of the same; natural size. Fig. 15, pollen mass, or bee-bread of 

 Osmia lignaria ; natural size. It is made up of distinct pellets of pollen, which 

 are probably stuck together with saliva. 



