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NOTES ON THE ANATOMY OF HEMUIEBUS TALPOIDES. 



By K. JORDAN, Ph.D. 

 (Plate XVllI.) 



WHEN stndyicig the insect described as Ari.n'tiia esaa on jip. 31:5-:52(; ul' tliis 

 Journal it was necessar}- to compare the morphology and anatomy of" 

 llntihiK'nis talpoides, the peculiar parasite found on Cricetomys apparently 

 thronghout tropical Africa. We have au account of the morphology of llemimertis 

 by Hansen, accompanied by very neat figures*; but of the internal anatomy 

 hardly anything is known, except that Hansen found in the body of a female a 

 number of embryos, one of which he figures. Mr. N. Charles Rothschild was in 

 possession of a few specimens of Ilemimcras collected by Mr. A. F. R. Wollaston 

 on the Ruweozori Expedition, a male and several females, and these he put very 

 kindly at my disposal. Although the soft parts were but indifferently preserved, 

 the facts ascertained advance our knowledge of this interesting insect, and appear 

 to be worth publishing. 



Hansen considered his specimens as being identical with //. talpoules Walk. 

 Sharp,t however, believed them to be " probably distinct,'' and called them 

 hanseni. Subsequent writers | have shown, however, that so far only one species 

 of Uemime.fus is known, hanseni being considered a synonym of talpoides. I have 

 com{)ared AValker's specimens with individuals from various districts of Africa, and 

 found them to be all, specifically, the same apart from a slight difference iu 

 length and width. 



Our account of the anatomy of llemimeriis confirms another opinion expressed 

 by Hansen. The relationship of Hemimerus was very obscure before the appearance 

 of Hansen's paper. In that excellent treatise the opinion was advanced on good 

 evidence that Hemhnertis was nearly related to the earwigs. Subsequent writers, 

 especially Verhoeff, § have accepted that view, and we also are in complete agree- 

 ment with it. The similarity to Blattids is purely superficial. 



One of the most interesting and jiuzzling points in Ileinimerus is the ijuestiou 

 as to its food. Hansen suggested that the insect might feed on " other small 

 parasites " of the rat; but there is no evidence whatever that Hendmerus attacks 

 other insects. Vosselerjl, in IflOC), gave a very interesting account of the habits 

 of Hemimerus, and entered at some length on the (juestion of its food. From 

 the state of the skin of the live host Vosseler arrived at the conclusion that 

 Hemimerus derives its nourishment from the skin by eating the epidermis, not 

 only the outer dead layers, but down to the roots of the hair. Unfortunately 

 Vosseler had, it seems, no microscope, as otherwise he could hardly have abstained 

 from further substantiating his observations of the live host and life 2iii''asites by 

 examining the contents of the alimentary canal of the insects. There is one very 

 suggestive point in Vosseler's account. The rat does not try to get rid of the 

 parasites, but acts as if it were entirely indiflFerent to them. Now, if the parasites 

 attack the .skin of the host down to the live cells, so as to cause patches bare 



» Tidshr. Ent. xv. pp. 65-93. t. 2, 3 (ISUl). 

 t ('amhridijc Nat. HiH. v., Insects i. p. 218 (1895;. 



% Poche, Xool. Aii:tiger xxv. p. 608 (l'J02); Uouvier, Bull. Soc. Ent. France, p. 170 (inoi;); Saussure, 

 Uev. Suisse Zool. iv. p. 227. t. 10 (189(i). 



§ fiitth. Nat. Fremule IlcHin, p. 87 (1902) 

 || Zool. Aiaeiyer xxxi. p. 13G (19UG). 



