432 Insect Architecture. 



horse or an ox, take refuge in the water, it has recourse 

 to a rut or dry dusty road, holding its nose close to the 

 ground, thus rendering it difficult for the fly to get at the 

 nostril. 



a, The belly of the grub. 6, Its back, c, The tail of the grab, greatly magnified. 

 d, The bump, or gall, having its external aperture filled with the tail of the grub. 



When the egg of the ox breeze-fly (Hypoderma bovis, LATR.) 

 is hatched, it immediately (if Mr. Bracey Clark be correct) 

 burrows into the skin ; while, according to Reaumur, it is 

 hatched there. At all events, the grub is found in a bump 

 on the animal's back, resembling a gall on a tree, " a 

 place," says Reaumur, " where food is found in abundance, 

 where it is protected from the weather, where it enjoys at 

 all times an equal degree of warmth, and where it finally 

 attains maturity."* When in an advanced stage, the bumps 

 appear much like the swellings produced upon the forehead by 

 a smart blow. These, with the grubs, are represented in the 

 foregoing figure, and also at page 434. 



' Every bump, according to Reaumur, has in its inside a 

 cavity, which is a lodging proportionate to the size of the 

 insebt. The bump and cavity also increase in proportion to 

 the growth of the grub. It is not until about the middle 

 of May that these bumps can be seen full grown. Owing 

 to particular circumstances, they do not all attain an equal- 

 * Mem. iv. 540. 



