156 HYMENOPTERA. 



We have received from Mr. Angus deserted cells of Cera- 

 tina in a syringa stem, in "which we detected a pupa of an 

 Odj-nerus, perhaps 0. leucomelas ; the cell was a little shorter 

 than that of the Ceratina it had occupied. The cocoon of 

 the Odj'ncrus Avas of silk, and almost undistinguishable from 

 the old cocoon of Ceratina. The wasp had dispensed with the 

 necessit}^ of making a mud cell. If future research shows that 

 either this or any other species makes a mud cell or not at 

 will, it shows the intelligence of these little " free-agents ; " 

 and that a blind adherence to fixed mechanical laws does not 

 obtain in these insects. 



The larvae of Odynerus and Eumenes are carnivorous. I 

 found several cells of 0. cdbopJialeratus., June 22d, in the 

 deserted nest of a Clisiocampa, which were stored with micro- 

 lepidopterous larvae and pupae, still alive, having been para- 

 lyzed by the sting of the wasp. The larvae of the wasp was 

 short and thick, being, when contracted, not more than tAvice 

 as long as broad ; the rings of the bod}' are moderately convex, 

 and the pleural region is faintly marked. Prof. A. E. Yerrill 

 has discovered the cells of an Od^-nerus at New Haven, forming 

 a sandy mass (Plate 5, Fig. 12) attached to the stem of a 

 plant. 



In Eumenes the lingua is very long, being narrower and 

 more deepl}^ divided than in Odynerus ; the second subcostal 

 space of the wings is long and narrow, while in Odynerus it is 

 triangular. The genus is easih^ recognized b}' the ver}- long 

 pedicel of the abdomen. Eumenes fraterna Say constructs a 

 thin cell (Plate 5,* Fig. 15) of pellets of mud, and as large 



* Explanation of Plate 5. Fig. 1. Mouth of the tunnel of Augochlora purus ; 

 from Emevton; Fig. 2. Cells of Osmia pacifica ; communicated by Mr. Sanborn. 

 Fig. 3. Vertical section of nest of Vespa with a group of primitive cells surrounded 

 b}' one layer of paper, and part of another; from Saussure. Fig. 4. Xest of Po- 

 lisfes annularis; from Saussure. Fig. 5. Three primitive cells of Polistes; ft a, top 

 view of the same, one being eggless. The sides adjoining are angular. Figs. G and 

 6fl!, a cell farther advanced, consisting of four cells, each containing an egg, and 

 with the edges of the cells built up higher and more decidedly six-sided: original. 

 Fig. 7. Cells o{ Icaria grittatipeiuiis. showing that each cell is built up independently 

 in regular hexagons. Fig. 8. Ground plan of a similar nest. Fig. 9. Ground plan 

 of cells of Tatua moi-io ; from Smith. Fig. 10. Ifest of Mischoci/itrtriiii lahiaitis ; 

 from Saussure. Fig. 11. Nest of Apo'ica pallida ; from Saussure. Fig. 12. Nest of 

 Odynerus: original. Fig. 13. Nest of Odynerus albophalernfus! original. Fig. 14. 

 Mud cell of Pelopceus flavipes : original. Fig. 1.5. A row of spherical cells of Eu- 

 menes fraterna, with the female; original, from Harris. 



