XX. THE HEMIPTEROUS FAMILY 

 POLYCTENID.E. 



By Dr. P. Speiser. 



There are among the parasites of bats very singular forms ; but 

 we are far from an even nearly complete knowledge of these small 

 animals, because bats seldom receive attention from sportsmen. 

 Several forms of these parasites, and specially interesting ones too, 

 are known only from a few isolated individuals. In the genus 

 Ascodipteron, which forms one of the best characterised families, 

 only five females are known, and no male ; while examples of an- 

 other parasitic genus {Polydenes) , of which I have recently received 

 a specimen by the great kindness of Dr. N. Annandale, of the 

 Calcutta Museum, are likewise rarities. I take the opportunity, 

 therefore, to give here a more complete review of the family they 

 represent. 



In 1864 Giglioli described the parasite of a Molossid from 

 Amoy, in China, under the name " Polydenes," which was proposed 

 to the author by Westwood. At that time no other insects from 

 bats but Diptera were known; these Diptera were all classified 

 together as " Nycteribiidse," and therefore the new genus 

 was placed in the family Nycteribiidae. The family '' Streblidse," 

 founded in 1862, contained winged species only, Polydenes being 

 wingless. Westwood took occasion later, having got a second 

 species, to examine the first one known in the exactest manner. In 

 his Thesaurus Entomologicus Oxoniensis he gives very much enlarged 

 and carefully delineated figures of all details. He ascertained thus 

 that Polydenes undergoes an ametabolic metamorphosis, and that 

 it has a three-jointed proboscis. 



As these characters, both important, do not allow the species 

 to be placed among the Diptera, he brought the genus into the 

 Anoplura by the side of the true lice and the bird-lice (Mallophaga). 

 C. O. Waterhouse, who was able to describe in 1880 another 

 American species, called attention to their relationship with the 

 Hemiptera, and not with the Diptera. But these singular parasites 

 came by rare exceptions only into museums, and therefore few 

 scientists knew them by a personal examination. The few notes 

 on their systematic position were disregarded, and the Polyctenida- 

 were still enumerated as late as 1896 among the Dipterous family 

 Nycteribiidae. Finally, I was able to examine two new species 

 myself and to point out the systematic position in a more exact 

 manner. These insects are true Hemiptera Heteroptera, and must 

 be placed in the strictest relationship to the bed-bug. They have, 



