301 
MODERN SYSTEM. 
five articulations, the first three gradually shorter, the fourth longer 
and wider, the fifth shorter, and receiving the didactyle claw : abdo- 
men in liolh sexes with eight joints: Female? with the first seg- 
ment of the back produced, the fourth and remainder partly con- 
cealed, the last segment at its apex furnished with a setigerous 
style: Male? with the last segment largest. 
Its situation was referred to the Diptera by Latreille, who ob- 
serves, in a note, that it may probably be found hereafter to consti- 
tute a peculiar Order of insects. From the apparent want of an- 
tennae, and from the confluence of the head and thorax. Dr. Leach 
placed it amongst the Acachnuida, in a division by itself. Its mode 
of propagation is unknown. Hermann considered the sexual as spe- 
cific differences. 
Sp. 1. Nyct. Hrrntanni. 
Phthiridium biarticulatum. Herm.Mem. Apt. 124 .pi. 6 .fig. 1. Offers, 80. 
Ilippobosca Vespertilionis. Scfir. Fn. Brit. ''.jit?. Phthiridium Her- 
manni. Leach, Encycl. Brit. Sapp. vol. i. 446. pi. 23. — Zuol. Misc. id- 
55, pi. 144. 
In the plate given in the third volume of the Miscellany, repre- 
sentations are given of the sexes very much magnified, with one leg 
still more highly increased by the aid of the microscope. The se- 
cond joint of each tibia is longer than all the joints of the tarsus 
taken together. 
Inhabits the greater and lesser horse-shoe bat. 
