new Species of Exotic, Hymenopterons Insects. 231 Nigro-caerulea, rude et vage punctata. Mesotliorax dorso antice baud linea media longitudinal! impressus, parapteris laterali-bus tamen distinctis. Metatliovax ut in C. compressa striatus, angulo aj)icali utrinque in tuberculum parvum acutum pro-diicto. Abdomen concolov, rude punctatus, apice griseo-villosum. Pedes cyanei, femoribus magis caeruleis ; tarsis nigris, articulo 4to lobato, minori tamen quam in speciebus reliquis. Alae fiiscescenti-hyalinse, nubila subapicali obscu-riori in cellula marginali, 2a et 3a subapicalibus et ad angulum analem extensa. Another species received from the banks of the river Gambia by the Rev. F. W. Hope in great numbers, appears to have been figured by Guerin under the name of Ampulex coinpressiventris, in the Iconographie du Regne Animal. The typical species, Am. coviprcssum, is, I believe, identical with the Sphex rujilumbis of Lichtenstein. The European species figured by J urine ought evidently to con-stitute a distinct subgenus ; the armature of the head, the difi^erent arrangement of the veins of the wings as figured in outline by Jurine, and the elongated and apparently simple feet, are charac-ters distinct from those of the true species of Chlorion proper. XXXVI. Description of anew Genus of Apterous Hexapod Insects found near London. Bij J. O. Westwood, Esq., F.L.S.' [Read February 7, 1842.] At the November meeting of this Society in 1840, I exhibited drawings of a minute wingless insect, which, as it would nor accord with the larvae of any known group of insects, I was in-duced at the time to think might possibly constitute a new genus of myriapodous insects in an undeveloped state. I had found this insect, which is scarcely a quarter of an inch long, running very quickly amongst the roots of flowers at a little distance below the surface of the ground, in which situation I had also detected immature Ltthobii, Jnli, and other Myriapoda ; and, moreover, finding in this insect a number of minute appendages arranged in pairs on the under surface of the abdominal segments, I at once