Iv. Jordan and N. C. Rothschild 
25 
Siphonaptera, is best visible in the bat-fleas ( Ischnopsyllus), in which 
the sternum is much longer than in the true Pulicidae. The posterior 
portion of the mesosternite, namely, the epimerum, has in Loemopsylla 
the same shape as in Pulex irritans, being much smaller than in the 
New World non-combed Pulicidae. - The ventral posterior edge of this 
epimerum recedes obliquely upwards, the stigma, which is situated 
