(ESTRID*.- 



-INSECTS.- 



-Glossixa. 



273 



they more particularly affect damp meadows, and appear 

 in the perfect state in the autumn. This is the fly 

 whose larva is commonly called the grub by farmers. 

 Species belonging to the fiimily Bombylidaj are amongst 

 the most interesting of this tribe of insects. Their 

 appearance is somewhat that of a small Humble-bee ; 

 they fly with great velocity, and, like hawk-moths or 

 humming-birds, suspend themselves by a rapid vibra- 

 tion of their wings, hovering over flowers, and by means 

 of their long jiroboscis e.xtracting the nectar upon which 

 they .subsist m their pei-feet condition. The loud hum 

 which they make whilst thus feeding, gives them a closer 

 apparent resemblance to the Bombi. The family is for 

 the most part exotic, some species being extremely 

 beautiful. 



We must briefly refer to these insects in their 

 annoying or destructive connection with quadwipeds. 

 Those belonging to the genus Tahamis (see Plate 11, 

 fig. 9, T. iiiijcr), are well known iu this country under 

 the name of Breeze-dies from the loud buzzing noise 

 which they make when on the wing; their approach 

 strikes with terror whole herds of cattle, which instantly 

 rush off with headlong speed on hearing the hum of 

 these relentless tormentors. DilTerent animals are 

 attacked by different species of flies ; a few may be 

 briefly enumerated. Fig. 172 gives a representation 

 of Tabanus buriims, and also a front and lateral view 

 of the parts of the mouth. 



Fig. 172. 



Tab,iuiis boviiuis. 



The Tuhanns bovimts attacks cattle, piercing their 

 skins and sucking their blood in such a manner as to 

 cause great pain ; the larva of this insect lives in the 

 ground. 



THE (ESTP.ID5;, commonly called Bot-flies, attack 

 various quadruiieds, each species of fly being parasitic 

 upon a particular animal. Thus the Gad-fly {(Estrus 

 bovis) attacks oxen; this fly is about the size of a drone- 

 bee, and not unlike it in colour; the female fastens 

 herself on the back of the animal, piercing the skin, 

 and then depositing an egg in the puncture. The 

 larvaj by their suction cause small abscesses, which 

 increase in size as larvje grow, and may be frequently 

 observed in great numbers on the backs of oxen and 

 cows. When the larvje are full gi-own, they emerge 

 from these swellings and fall to the gi'ound, creeping 

 into any suitable hole for shelter, when they shortly 

 undergo their change to their perfect condition. 



It would appear that some members of this family 



have been known even to attack man. Humboldt 



observed this in South America, the Indians being 



covered with small tumoiu's caused by the (Estrus 



Vol. U. 



Ilominis. The (Estrus Equi deposits its eggs on the 

 hairs of the horse, in such parts of the body that the 

 horse, by licking, will be sure to convey them into its 

 stomach; the larva is the cause of the disease known 

 as the hots. (Est.nis Ovis attacks sheep, the larva 

 living in the frontal sinus of the head. The reindeer 

 is attacked by the (Estrus tarandi; the appearance of 

 two or three of these flies is said to alarm a whole herd 

 of deer, so dreadfully are they tormented by them. 

 TheCEstrus follows the herd wheresoever it may retreat, 

 and however rapid its flight ; it is not deterred, even 

 should the deer flee to the snow-covered mountains. 

 There is uo escaping from these fearful tormentors ; 

 the fly bores a hole in the skin of the deer, in which it 

 deposits an egg. The larva; continue to feed until full 

 grown, when their presence is known by a swelling 

 observable on the hide of the animal as large as the 

 egg of a pigeon. The attack of six or eight of these 

 flies is sufficient so to emaciate the deer that great 

 numbers perish. The (Estrus Ccrvi attacks the fallow 

 deer. Fig. 173 is that of (Estrus tromjK, with its 

 larva and pupa. This species attacks the deer, depo- 

 siting its egg in the nostrils of the animal ; the larva 

 feeds in the frontal sinus of tlie head. 



1, Oi^strus trompe: 2, the Iar\a ; 3, the pupa. 



The Zimb, described by Bruce the African traveller, 

 is one of the most formidable and destructive species 

 known ; this fly attacks its victim on all parts of the 

 body, producing large bosses and ulcers, which in the 

 end putrefy, and thereby inevitably cause the death 

 of all animals which it attacks. 



Another equally destructive species of fly was dis- 



Fig. 174. 



Tse-tse (Glossina morsitnns.) 



covered by the celebrated African explorer, Dr. Living- 

 ston ; this is the Tse-tse described scientifically by Mr. 

 Westwood as Giossena /norsf'tons. (Fig. 174.) This pest 



2 M 



