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CONTRIBUTION TO OUR KNOWLEDGE OF THE MORPHO- 

 LOGY AND SYSTEMATICS OF THE POLYCTENIBAE, 

 A FAMILY OF RHYNCHOTA PARASITIC ON BATS. 



By Db. K. JORDAN. 



(With Plates XII., XIII., XIV.) 

 MONG the in.sects entrnsteil to ns by the authorities of the British Mnsenm 



A 



(Natural History) for the purpose of identification we found some forms of 

 Polyctenidae which did not agree with any of the figures published by Horviith, 

 Speiser, Waterhouse, and others, and necessitated, therefore, a closer research 

 into the literature on the subject, and a comparison of the allied species, before 

 the supposed new forms could be considered as hitherto unknown to science. We 

 had the good fortune of being enabled to study in the British Museum the types 

 ol Pobjctenidae, i.e. the nomenclatorial types, contained in that institute, and which 

 the authorities on this family had not seen, as tyjjcs cannot be lent out by the 

 British Museum. Having once embarked upon the task of comparing the 

 unidentified forms with the types, figures, and descriptions, we soon found that 

 the material of the British Museum collection, together with the specimens 

 received by the Entomological Research Committee (Tropical Africa), placed us 

 in such a favourable position that we deemed it advisable, for the sake of other 

 students of this group, to enter more closely upon the subject. 



The Polyctenidae are only known from bats in the Tropics and Subtropics 

 of the Eastern as well as the Western Hemisphere, and appear to be very rare. 

 The collection of the British Museum comprises only 27 specimens ; but this 

 number is very large in comparison, as less than a dozen specimens are men- 

 tioned as being contained in other collections. This rarity is not merely apparent, 

 as in the case of so many other insects, but is real, we believe. The e.xphuiation 

 of the rarity lies in the fact that the Pob/cfenidne are viviparous, and produce 

 the young in such a very advanced stage that the progeny must necessarily be 

 exceedingly limited in numbers. The discovery of the method of propagation of 

 these parasites is entirely due to the removal into balsam of some specimens 

 from the cardboard on which — unfortunatelj- — they were pasted. We hope that it 

 will not be considered impertinent on our part if we draw attention to the 

 necessity of preserving Polyctenidae either in alcohol or mounted on a slide. As 

 everybody who has studied these insects knows, the underside offers very important 

 taxonomic characters. The number of segments in the rostrum, the structure of 

 the first anteunal segment, the shape of the throat-part of the head, the outlines 

 of the sterna, and the number and jiositiou of the bristles on the under surface are 

 in several instances far better (and sometimes the only sure) guides in identifying 

 allied species than the upper surfoce, and it goes without saying that these organs 

 must be compared if an attempt at classifying the species is made. t'arded 

 specimens, which only exhibit the upper surface (carrying a coat of minute dust 

 revealed under the microscope), and, when soaked ofl" the card, show the under 

 side smothered in glue or shellac, are very distressing. We find it most con- 

 venient for all purposes if some specimens of a species are kept in alcohol and 



