STATE AGRICULTURAL SOCIETY. 
851 
RYE-FLY. THESE FLIES ARE NOT PARASITES. 
some other circumstance to indicate its existence. But the only 
evidence we have that an insect of another kind occurs in the dis¬ 
eased grain for these Chalcidians to prey upon, is the larva which 
I saw in the Virginia wheat from Mr. Rives. I cannot doubt but 
that was a Cecidoinyia larva. I therefore have carefully cast 
over in my thoughts the circumstances under which this larva 
was found, and I am led to suspect that there might have been 
an error attending it. According to the recollection which I 
have, the description I gave was drawn up from a single speci¬ 
men, this being the only perfect specimen which I met with in 
the stalks. All the others were smaller, discolored, and so soft I 
judged them to be in an incipient state of decay and putridity. 
I now suspect these smaller, tarnished individuals, were the real 
joint-worms, and that the worm from which my description was 
taken was a larva of the Hessian fly, which happened to be pre¬ 
sent in the same stalk; and that the structure of the stalk was 
so much confused and obliterated that I did not and perhaps 
could not ascertain with certainty whether this particular worm 
was lying in a cell which was perfectly closed, like those in which 
the other worms were lying, as I took it for granted that the 
worms were all of one kind and that their cells would conse¬ 
quently be alike. I hasten to state these circumstances, lest an 
importance be attached to the occurrence of this Cecidomyian 
larva in the Virginia wheat, which it may not, after all, be 
entitled to. 
12. Yellow-bellied Janus, Janus Jlaviventris, new species. (Hymenoptera. 
Tenthredinidso.) 
13. Thhee-stotted Cepiius, Phyllcrcus trimaculatus, Say. (Hymcnoptera. 
Tenthredinidffi.) 
In rye fields towards harvest time, scattering heads of tho grain remaining erect and having 
a prematurely ripo appoarancc, the straw bored its whole length by a footless worm a half 
inch long. 
Iii Europe ono of the insects most noticed by writers as inju¬ 
rious to the rye crop is a saw-fly three tenths of an inch long, of 
a shining black color, with a bright yellow mouth, legs, and spots 
on its hind body. It is named Cephus pygmceus, and forms the 
lype of a small group, named Cep/ndes, in the family Tenthredi- 
nida. It resembles a small wasp, except that its fore and hind 
body are closely united together, and not separated by the strong 
contraction which is observed in the wasp. This fly becomes 
common in the rye fields towards tho end of May, the female 
