In previous numbers of the Can. Ent. (vols. ix, p. 232, and viii, p. 137) I have given an account of a singular larva found in thorns of Gleditschia triacanthos or Honey Locust. I have never succeeded in rearing the imago from the larvæ found in the thorns, but the same larva—or one that I have not been able to distinguish from it—lives also in the pith of the “iron weed” ( Veronia ) and also in that of the “hog weed ” or “horse weed,” Ambrosia trifida ; and in the pith of these stems is also found a Lepidopterous larva which I have not been able to rear to the imago state, but which does not seem to differ from that of Laverna gleditschæella found in the thorns.