175 



Diptera. The structure of the ovipositor clearly excludes the possi- 

 bility of puncture, for, though horny, it has a blunt trifid tip, and is 

 beset at the end with certain minute hairs, and structure of this char- 

 acter is a very safe guide to habit. Figure 35 is drawn so as to show 

 the telescopic and extensile nature of this organ. 



The excitement, amounting often to frenzy, which has been noticed 

 in cattle when the bot-flies are ovipositing, and which has probably led 

 to the idea of stinging, results from the instinctive dread of the fly 

 rather than from any real pain, though no doubt the secretion which so 

 firmly fastens the eggs is accompanied by an irritating sensation. This 

 will account for most of the supposed cases of stinging, including the 

 case of the man-infesting bots. ( Vide Insect Life, Vol. I, pp. 76 and 

 226.) In the case of the horse Bot-fly or the sheep Bot-fly, where it is 

 well known that the eggs are not inserted, the animals exhibit a similar 

 dread and nervousness. The fact that the egg has been observed partly 

 extruded from the fly about to oviposit also bears on this point. 



Mr. Bracy Clark, in " An Appendix or Supplement to a Treatise on 

 the (Estri and Cuterebra3 of Various Animals"* (Transactions Linncean 

 Society, London, 1843, Vol. xix, pp. 81-94), which treatise was but an 

 elaboration of the paper already mentioned by us, after describing the 

 peculiar noise of the parent fly which is apparently so frightful to cat- 

 tle, says: 



We may also further observe that there can not be any very painful affliction, as 

 the fly has really no instrument fitted for such a purpose, the feminine ovipositor be- 

 ing a mere tube, made of flexible materials, piece inserted in piece, exactly as in the 

 common telescope. However, it is possible on reaching the skin or cuticle of the 

 beast, which is always highly sensitive in these hairy animals, tbat it migbt produce 

 a degree of uneasy tickling, which, added to the noise, and perhaps an instinctive 

 fear, always impressed upon them, is altogether sufficient for the extraordinary alarm 

 we see. 



F. Brauer, in his Monographic dcr (Estridcn 

 (1863), while stating that the manner of placing 

 the egg is still obscure, does not think that the 

 egg is inserted into the hide. He has found also 

 what he supposed to be the newly hatched larva 

 in the first layers of the skin near the exterior 

 surface. 



Miss Ormerod was at first strongly inclined to 

 believe that the eggs are deposited below the 

 skin, but in her latest pamphlet on the subject 

 she says that the egg is probably deposited on 

 the surface, and that the newly hatched maggot 

 makes its way through the skin by means of the fig. 35. —Hypoderma bovis, 

 sharp, cutting hooks clothing its body surface. ovipositor of female: a, 



T „ , . . - from side ; b, tip, from be- 



In Support Of tlllS She SayS : low-enlarged (original). 



'An essay on the Bots of horses and otber animals, Loudon, 1815 



