HARD WICKE ' .S S CIE NCE - G O SSI P. 



109 



Aphaniptera, or fleas, should be placed, to consider 

 first those more highly organised parasites supplied 

 with wings, etc., and work down the scale till we 

 reach the genus Demodex or Hypopus, among the 

 Acari, whose structure is extremely simple. The 

 subject of vegetable parasites, generally of a fungoid 

 type, such as that occasioning ring- worm, I do not 

 propose touching upon, nor yet that large and inter- 

 esting subject of Helminthology, so ably treated 

 of by the late Dr. Cobbold. 



Tutting aside, then, such insectsasmosquitoes, horse- 



flying, the species of the genus only being able to take- 

 short flights, which are little more than leaps. Their 

 mouths are formed for suction, and from their large 

 size these parasites must be injurious. The grouse, 

 owl, plover, and several other birds, are the hosts oi| 

 this genus. Next we may mention the Stenopteryx 

 hirundinis, an insect about the same size, and very 

 like the last, except that the wings are merely rudi- 

 mentary. It is found about the nests and upon the 

 young of the swallow. Passing still further down the 

 scale we come to the Melophagus ovinus, or sheep- 



I' '£• 74- — Parasite of Flying Fox, 2 . X 20. 



flies, etc. — some of which suck the blood of their host, 

 but do not make their dwelling there, while others 

 lay their eggs beneath their skins, and whose larva? 

 are nourished there, and which consequently are, for 

 at least a part of their lives, true parasites — we find, 

 as perhaps one of the most highly organised, or at all 

 events very nearly allied to the Diptera, the genus 

 Ornithymia (Fig. 72). This genus contains several 

 species, all of which are of large size, being but little 

 smaller than the common bluebottle fly, and equipped 

 with a pair of well-developed wings, though they, 

 probably from disuse, do not seem of much service for 



tick, called in Scotland the kade, and which is too 

 well known to require description, beyond the fact 

 that it is not a tick at all, and is entirely distinct from 

 the proper sheep-tick, which is a species of Ixodes. 

 Closely allied to this is the genus Lipoptena, found 

 upon the stag (see Fig. 73). In both these genera 

 the wings have entirely disappeared. We may here 

 mention that curious and beautiful genus, the Nycte- 

 ribiidas, which is only found on bats. Those who 

 wish to study this genus will find an able article in 

 the " Transactions of the Zoological Society," vol. i. 

 p. 274. Fig. 74 shows the peculiarities of this parasite 



