144 [September 



the great bulk of them hybernated either in larva or pupa state and 

 came out May 8th — 20th. They vary but little. I have beaten larvae 

 of very similar appearance off oak trees." 



So far as I am informed, the larvae is unknown to European lepidop- 

 terists, although it is recorded that the perfect insect, prseanguAta, is 

 very common among willows and poplars in July, and may frequently 

 be observed sitting on the trunks of those trees with the anterior feet 

 put back, like BedeUln^ and the head raised a little. 



Mr. Walsh has the honor of having made an interesting discovery, 

 that puts an end to all uncertainty respecting the larva and its food 

 plants. 



In a subsequent letter Mr. Walsh kindly supplied me with the follow- 

 ing description of the larva : 



" Length .20 inch. Body tapering at each end, opaque, milky- 

 whitish, with a few short, whitish hairs. The first segment behind the 

 head, with an obsemicircular, shining, glabrous, brown, dorsal shield; 

 second segment with an interrupted, opaque brown, dorsal band on its 

 anterior edge, the interruption occupying about one-third of the band; 

 segments 3—12 with an uninterrupted opaque brown, dorsal band on 

 the anterior edge, and segment eleventh with a similar band at its tip 

 also. Head yellowish. Legs and venter immaculate, whitish. Legs 

 six, prelegs ten, normally arranged. Spins a thread, wriggles much 

 when disturbed and runs backwards with great agility. 



" This larva occurred in abundance Aug. 2ord, and subsequently in 

 the Tenthredinidous gall, S. po77iuni Walsh MS., which grows on the 

 leaves of Salix cordata. Each gall contained but a single larva, unac- 

 companied by the larva of the JVematus which makes the gall, which 

 it must consequently have destroyed or starved out, either in the egg 

 or in the larva state. 



" A single imago came out in the autumn of the same year, but the 

 great bulk of them came out next spring, May 8 — 2U, from galls kept 

 through the winter. There can be no doubt of the correlation of larva 

 and imago, because no other lepidopterous larva or imago occurred in 

 the gall S. pomum, though I had three or four hundred of them in 

 my breeding vase. The insect must hybernate normally in the larva 

 state, for I noticed numbers of them in the spring crawling about 

 among the galls. In a state of confinement, it generally retires to the 

 inside of the gall to assume the pupa state, though I noticed one or 

 two cocoons spun among the galls. Probably in a state of nature it 

 hybernates in the gall, comes out of it in the spring and spins its co- 

 coon amongst dry leaves and rubbish. 



