478 INSECTA. 



the extremity, and terminate at the origin of the wings. As elytra, 

 properly so called, always cover the whole or the base of the latter 

 organs and arise from the second segment of the trunk, these bodies 

 are not true wing-cases, but parts analogous to those (pterygoda) 

 we have already observed at the base of the wings in the Lepidop- 

 tera. The wings of the Rhipiptera are large, membranous, divided 

 by longitudinal and radiating nervures, and fold longitudinally in the 

 manner of a fan. The mouth consists of four pieces, two of which, 

 the shortest, appear to be so many biarticulated palpi; the others 

 inserted near the internal base of the preceding ones, resemble little 

 linear laminae, which are pointed and crossed at their extremity like 

 the mandibles of various Insects; they bear a greater similitude to 

 the lancets of the sucker of the Diptera than to true mandibles. 

 The head is also furnished with two large hemispherical, slightly 

 pediculated, and granular eyes; two almost filiform and short an- 

 tennas, approximated at base on a common elevation, consisting of 

 three joints, the two first of which are very short, and the third very 

 long, and divided down to its origin into two long, compressed, lan- 

 ceolate branches, laid one against the other. The ocelli are want- 

 ing. The form and divisions of the trunk are very similar to those 

 of several Cicadariae, Psyllae, and Chrysides. The abdomen is 

 almost cylindrical, consists of eight or nine segments, and is termi- 

 nated by pieces also analogous to those observed at the extremity 

 of the above mentioned Hemiptera. 



These Insects, in their larvae state, live between the abdominal 

 scales of several species of Andrenae and Wasps of the subgenus 

 Polistes. They frisk about with a simultaneous motion of the wings 

 and halteres. Although they appear to be removed in several res- 

 pects from the Hymenoptera, I still think it is to some of those In- 

 sects, such as the Eulophi, that they are most nearly allied. 



M. Peck has observed one of the larvae — Xenos PecTcii — which 

 is found on Wasps. It forms an oblong oval, is destitute of feet, and 

 is annulated or plaited; the anterior extremity is dilated in the form 

 of a head, and the mouth consists of three tubercles. These larvje 

 become nymphs in the same place, and, as it appeared to me, when 

 examining the nymphs of the Xenos Rossi, another Insect of the 

 same order, within their own skin, and without changing their form. 



Nature has perhaps furnished the Rhipiptera with the two false 

 elytra of which we have spoken, to enable them to disengage them- 



