OS NATURAL HISTORY. 



birds, while those which have lost their wings occur on quadrupeds. Thus Lipoptena cervi occurs 

 wingless upon the Stag, and with wings upon Grouse ; in the latter condition it has been described as 

 distinct under the name of Ornithobia pallida. Many other species live upon birds ; sometimes, as 

 iu the case of Ornit/tomyia aviculari-a, infesting many kinds of birds ; sometimes confining themselves 

 to particular species or genera, such as Stenopteryx hirundinis, which is particularly abundant upon 

 young Swallows. 



FAMILY XXII. NYCTERIBIID^E. 



The Nycteribiidae are exclusively parasitic on Bats, and hence are commonly known as " Bat 

 Lice." They are wingless, but have a pair of halteres placed upon the dorsal surface between the 

 articulations of the posterior limbs. The head is very movable, and is usually carried thrown back 

 into a cavity of the upper surface of the thorax ; the eyes are small or deficient ; the antennae attached 

 beneath the margin of the head ; the proboscis filiform, with very large palpi ; the long legs are 

 articulated quite on the sides of the thorax ; and the basal joint of the tarsi is very long. 



These are curious, ungainly little creatures, more like flattened Spiders than anything ; they 

 rarely exceed a sixth of an inch in length, and are parasitic upon various species of Bats, dwelling 

 especially in the cavity of the axilla. They are generally of a pale ochreous or leather colour, with 

 the claws black. The British species live on the common Bats, such as Vespertilio murinus and 

 V. serotinus, and are sometimes rather abundant. In collections they are rare. 



FAMILY XXIII. BRAULID^E. 



This third and last family of the pupiparous Diptera includes only a single minute species, which 

 is parasitic upon the Honey Bee, and seems to show a preference for the Drones. It has a large head, 

 with neither eyes nor ocelli ; short, two-jointed antennae, immersed in deep cavities of the forehead ; a 

 small, ring-like thorax with a large stigma on each side, and a nearly circular abdomen. The legs are 

 attached to the under surface of the body near the middle line, and the tarsi consist of four short 

 joints and a much longer one at the extremity, the last bearing a pair of singular claws in the form of 

 combs with long teeth. This Bee Louse (Braula cceca) is a minute creature about one-eighteenth of an 

 inch long, of a rusty-brown colour. It lives upon the thorax of the Bees, its remarkably pectinated 

 claws being particularly well adapted for clinging to the hairs with which that part is clothed. 



ORDER APHANIPTERA. 



This small order includes a few insects which are tolerably familiar to most people, namely, those 

 exceedingly active and very troublesome little creatures, the Fleas. As already stated, they have 

 been of late very commonly classed with the Diptera, but they differ so importantly from all true 

 members of that order that we have thought it better to keep them separate. How far this course 

 is justified will be seen when we have described the general characters of the insects forming the 

 group. 



In general form the body, as is probably pretty well known, is considerably compressed, and the 

 insect has no wings. The three segments of the thorax, instead of being soldered together to form a 

 single mass, are separate and similarly constructed, forming three narrow bands behind the head, the 

 only difference between them being that the second and third segments bear oil each side a peculiar 

 plate or soale-like piece projecting from their hinder margins. The scales of the mesothorax are 

 small, those of the metathorax much larger, and these parts have generally been regarded as 

 representing the two pairs of wings. Attached to these thoracic segments are three pairs of legs, 

 which are long and powerful. Their coxae especially are very greatly developed ; those of the front 

 pair of legs project forwai-d at the sides of the head, so as to protect the organs of the mouth, and 

 those of the hinder pair are the largest. The trochanters are small ; the femora broad and compressed, 

 especially those of the hind legs, which exceed the others in size, and are adapted for leaping ; and the 

 tarsi consist of five joints. The eyes are small and round, and the antennae are minute organs, composed 

 of four joints, and enclosed in little cavities immediately behind the eyes. In the structure of the 

 mouth (see Fig. c., p. 100) the Fleas both resemble and differ from the Diptera. The labrum is rudi- 

 mentary, but the labium forms a rather delicate membranous organ, which is cleft throughout a good 



