Two new Strepsipterous Insects. 53 



which I would propose the name of Hylecthrus, readily distin- 

 guished at first sight by the broad laminae of the antennse, which 

 are nearly of equal width throughout, whereas in Xenos they gra- 

 dually taper from the middle to the apex ; the veining of the wings 

 being also different ; the palpi less conspicuous in the former; and 

 the thorax considerably more gibbous, as well as wider and shorter 

 in proportion. 



It may furthermore not be unworthy of notice, that among the 

 hitherto described species of Xenos, a portion (including the type 

 of the genus) being parasitic upon the social lespidce, whose larvae 

 subsist on disgorged juices, chiefly of vegetable extraction, admi- 

 nistered to them from mouth to mouth in open cells, — whereas 

 another portion, being derived from the solitary and exclusively 

 carnivorous Sphegidce &c, reared in closed cells, wherein the young 

 hexapod must therefore be incarcerated at a time when, as in the 

 solitary Mellifera, the ovum and store only are to be met with, — 

 it seems reasonable to infer that, inasmuch as all remarkable varia- 

 tions of structure afford presumptive evidence of corresponding 

 modifications of economy, so, vice versa, habits thus widely differ- 

 ing will also be typified in the minutiae of some peculiar character, 

 whereby we may be enabled to discriminate the respective groups, 

 and associate the species justly appertaining to each. 



With reference to an opinion which has long prevailed, that the 

 larvae of the Hijlcei are parasitical feeders on the stores of other 

 Rlellifera, — founded upon apparent structural incapacity in the 

 perfect insect for the task of collecting and conveying nutriment 

 for its progeny, this inference does not appear to be borne out in 

 those which I have reared; for, having obtained a considerable 

 number of specimens from cells adapted to the size of the larvae, 

 and constructed in appropriate channels through the pith, forming 

 sometimes a double or triple series of parallel galleries, occasionally 

 crossing each other (as in the accompanying briar marked^.), the 

 peculiar transparent iridescent tapestry of the Hylcei being con- 

 tinued throughout each series of cells in uninterrupted succession, 

 I cannot but infer that these are no casual intruders or predatory 

 usurpers, but, on the contrary, rightful heirs of the original con- 

 structors and purveyors. 



Similar parasitical habits have also been ascribed to other 

 Hymenopterous insects, upon primd facie evidence of structural 

 organization, — such as the absence of pollen-plates and pollen- 

 brushes in the pollinivorous, or the non-existence of spinal arma- 

 ture of the tibiae, considered essential to the Zoophagous for the 

 transport of their prey, — which inferences, however, more careful 



