THE MICROSCOPE. 257 



these parasites progress from the pubes to the axilla, and then to 

 the eyelids, always upwards." 



Parasite from Flying Fox (PI. XVIII., Figs, i and 2). — This 

 belongs to the Nycferibiid(C, the very lowest among the Dip- 

 tera. It is a most anomalous form. I append figures of male 

 and female, to facilitate comparison of the parts in the two sexes. 

 " The second general section of the Diptera is composed of small 

 groups of parasitic insects of very peculiar structure, forming the 

 Linnaean genus, Hippobosca, and differing from the flies compos- 

 ing the former section ( ffii-Zr/afe) in the structure of the mouth, 

 the insertion of the antennae within the head, and of the latter 

 within the front of the thorax, the denticulation of the tarsal 

 claws, and the nature of their transformations." — Westwood, 

 '■'■ Ititrodiictioti to Modern Classification of Insects" Vol. II., p. 580. 



We owe much of our knowledge of these singular parasites to 

 Professor Westwood. As usual, he has paid great attention to the 

 parts comprising the mouth, and dismisses the subject as 

 follows : — An extract from Van der Hoeven (" Handbook of 

 Zoology," Vol. I., p. 311) will best precede: — "The bucal organs 

 pass into fine threads through a small opening ('Just like a thread 

 through the eye of a needle ' (Westwood)." 



They are three in number. " Being of unequal size, and con- 

 sequently single organs, they cannot represent either mandibles or 

 maxillae, and must therefore be regarded as the analogues of the 

 labrum, lingua, and labium " (Westwood, loc. cit., p. 582). The 

 determination is, however, acknowledged to be one of extreme 

 difficulty, and there seem to be scarcely sufficient materials as yet 

 whereby to settle the knowledge with sufficient precision. I hope 

 members who may have opportunities of studying bats will pay 

 special attention to their parasites. 



On a former occasion, the extraordinary way in which they 

 represent, with the Diptera, the Ixodidce amongst the acari, was 

 pointed out. The fusion in the $ of all the abnormal segments 

 beyond the first, to form a spider-hke body, strikes me as one of 

 the most singular points about it, the long hairs terminating it 

 even having their counterparts in those which guard the spinnerets 

 of spiders. In the male, as will be seen here, the abdominal 

 segments are as distinct and as moveable as in ordinary flies. 

 " The abdomen " (in Nycteribia) " is covered with a continuous 

 membrane, capable of great distension, which occurs in the 

 female, the larvae hatching and being nourished in that situation 

 until they have assumed the pupa state, when each is deposited in 

 the shape of a soft, white, roundish egg notched at one end, 

 without any trace of articulation, and nearly as large as the abdo- 

 men of the parent fly. Subsequently this puparium becomes 



