1903] NEEDHAM : — BUTTON-BUSH INSECTS 25 



brownish fluid which hardens and glues the old skin to the silk. Rhogas emerges 

 through a big round hole cut in the back of the larva, but the empty larval skin 

 may hang through several seasons, until bleached and weathered and bare. I 

 have found a number of them in early spring still attached, and well preserved. 



I bred many parasites from the larvae of this species, but only one moth ; that 

 one emerged on the 20th of July from a cocoon that was spun by the larva in the 

 top of a SciRPUS stem, within a nest made of deflexed bracts and flowering 

 branches fastened with silk to the side of the stem. That specimen and specimens 

 of the three next following species have been determined by Prof. John B. Smith. 



3. Eudryas grata (Fabr.). A single pupa of this species was found in spring 

 under the bark of a fallen button-bush stem, in a well-formed pupal cell, and was 

 bred indoors, the handsome moth emerging in May. 



4. Agrotis ypsilon Rott. ) A number of moths of these two species were 



5. Pliisia simplex Guen. ) seen visiting the button-bush flowers for nectar at 



dusk. 



6. Platysafnia cecropia (Linne). A single egg cluster of this species was 

 found on a button-bush leaf, and the larvae were hatched at home on July 2d. 

 Four small larvae were found in another place on a single leaf a few days there- 

 after. 



Hymenoptera. 7. Da kibohmia needhavii As\\mcdid. This species shares the 

 terminal pith cavities with Melanomma (No. i artte), but is much less common. 

 The first specimens were found in winter, hibernating in their cells as pupae. Ima- 

 gos were bred from these in May. On June 26th I first saw the live wasp. It was 

 a female, busily engaged in excavating the pith in the end of a broken stem. She 

 would descend into the stem and after a few seconds back up to the surface and 

 scatter some fine white pith chips, descend again instantly, and repeat. I marked 

 the place and returned the next day to find her storing her completed nest tunnel 

 with aphids — nymphs of Rhopalosiphum sp ? and Chaitophorus sp ? I 

 captured her then, and examined the nest, and found one cell completed and closed, 

 and a second one half stored. 



The completed nest consists of four or five cells arranged end to end in the 

 cavity, separated by partitions of fine pith chips, the thickness of the partition 

 being about equal to the diameter of the cell. It appears that the first boring into 

 the pith cavity is not of the full diameter of the cells, and that the chips made in 

 finishing the walls of each cell, except the bottom one, are used to form the parti- 

 tion separating it from the one below it. 



This species and the three named Hymenoptera next following have been 

 determined by Dr. Wm. H. Ashmead. 



8. Rhogas rileyi Cress. This big parasite of Acronycta oblinita has already 



