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f hair, the iiulifFereuce of tho host towards this destruction is very remarkable 

 indeed. If we meet with associations of this kind, the stronger leaving the weaker 

 unmolested, the explanatiun lies generally in the mutual benefit derived by both 

 jiarfies from their association, and we believe that the contents of the gut of 

 Hemimerus afford evidence that this is so also in the case of that insect and its 

 host. We have examined the gut of four specimens. The contents are the same 

 in all four, wliich may possibly lie explained by the specimens being perhajis 

 obtained from the same individual of ('r/retom>/s. The oesophagus and crop were 

 filled with a whitish matter, and the same substance was found in tlie other 

 divisions of the alimentary canal. In this mass is embedded everywhere a large 

 nnmber of variously sha])ed brown bodies, which [)rove to be the spores and 

 sporangia of fungus. There is also some dark amorphous matter, which may 

 have come into the alimentary canal accidentally with the food as dirt. I have 

 examined the epidermis (and the foreign matter covering it) of the two stuffed 

 specimens of Cricetonv/s contained in the Tring Museum. The specimens had been 

 living in captivity in England for some time before they came into the collection. 

 The scurf taken from these skins very much resembles the pale matter in the 

 alimentary canal of Hemimerus, and I also found some brown spores of fungns- 

 This result goes far to corroborate Vosseler's conclusion that Remhnerus feeds on 

 the epidermis of the host. But the presence of the fungus suggests that the bare 

 patches on the skin of Cricetomi/is are not caused by Hemimerus, but by a fungus, 

 and that the parasite becomes beneficent to its host by eating the fungus as well 

 as the scurf. We have at present no means to further investigate the problem, but 

 hope that some scientist resident in tropical Africa will be able to comjiare minntely 

 the food which has just entered into the oesophagus of Hemimerus with the surface 

 of the skin of the specimen of the host on which the parasite has been feeding. 



Alimentary Canal. 



The nutritive system is very similar to that of the earwigs. The divisions 

 of the alimentary ;are almost the same in shape and size as in Forji/sula auricularia.. 

 The oesojihagns {oe, PI. XVIII. fig. '!) is as lung as the stomach, ending abruptly 

 at the base of the abdomen. The short gizzard or proventriculus {pr) has the 

 same shajie as in Forfieula. Itsintima bears numerous minute transverse continuDiih 

 ridges armed with miuute teeth. At the base of the gizzard and along the centre 

 of the six longitudinal folds these ridges have developed into prominent teeth 

 (PI. XVI. fig. o). The six folds extend into the stomach as finger-like processes, 

 containing each a bundle of longitudinal muscles. Hansen, I.e., erroneously says 

 that there is no such armature in the proventriculus. The tips of these processes 

 are similarly armed as in Arixenia (PI. XVI. tig. 4), whereas the armature of 

 the other jiarts is diH'erent in the two insects. The stomach (sto), together with 

 the beginning of the small intestine, makes a single convolution, as in Forfcula 

 auricularia. The small intestine lies luidcrneath the convolution of the stomach. 



The Malpighian tubules are arranged in four bunches, as in the earwigs, 

 there being twenty odd tubules altogether (5, 5, 5, T). Two of these bunches 

 are dorsal and two ventral. 



On tlie posterior half of the oesophagus, and at both sides of it, there lie a 

 nnmber of small spindle-shaped salivary glands united to one large bunch with 

 a single duct. As I am not certain of the structure of the glands, I have not 

 drawn them. 



