372 INSECTS. 



are rather hump-backed little creatures, with deflexed, 

 fringed wings, entirely destitute of transverse veins, and 

 move with much activity. In the larval stage, some 

 species feed on decayed vegetable matter, while others 

 are supposed to be parasitic on other insects. 



The characters of the second section of Diptera, 

 EPROBOSCIDEA, have been given at page 339. 



The Eproboscidea are, as has been already said, all 

 parasitic, in the perfect state, in various birds and quad- 

 rupeds. The Forest-fly, or Hippobosca, is a well-known 

 example, as also the stout- bodied, wingless Melophagus 

 ovinus (PL XVI., fig. 6), or " Sheep-tick," as it is im- 

 properly called, remarkable as having the appearance of 

 two groups of simple, rather than a pair of compound 

 eyes. This is owing to the external faces being distinct 

 from each other, and round instead of hexagonal. These 

 insects are parasitic on horses, oxen, and sheep. Others 

 of the same family are parasitic upon birds, and the 

 swallow is especially subject to their attacks. 



An unusual circumstance occurs in this family, the 

 female giving birth to but one individual, and that not 

 until it has either already attained the last stage of larva- 

 hood or has become a pupa. 



The second family in this section contains only two 

 known species, parasitic upon bats, and very rare. They 

 are wingless, and of most singular appearance, the head 

 being thrown completely backwards, and carried in an 

 inverted position. They form the genus Nycteribia. 



With the Diptera, the most modern arrangements of 

 insects come to a close. There remain, however, a few 

 genera whose claim to rank as insects has so often been 

 urged, and whose appearance is so insect -like, that some 



