(ESTEUS. 387 



Genus (ESTRUS, L. 



CEstrus, Linuteus, Sj'st. Nut., Ed. x, p. 584 (1758), and Ed. xii, p. 969 

 (1767). 



Gexotype, CEstrus ovis, L. ; by designation of Cui'tis. 

 Head large, semicircular, broader than thorax; frons wide in 

 both sexes, slightly curved, vesiculose on each side, the puffed up 

 part extending downwards, gradually narrowing to lower margin 

 of eyes, leaving a depressed elongate triangle in middle of frons ; 

 anterior margin of frons overhanging antennal cavity ; the latter 

 comparatively shallow, the median ridge low or rudimentary ; 

 under side of head bare, swollen. Autennre short, ord joint 

 longer than 1st and 2nd together, subglobular, with long bare 

 dorsal arista ; a median shallow groove from antennal cavity to 

 mouth-opening; proboscis rudimentary, bifid and flat at "tip, 

 slightly prominent ; palpi short, globular ; eyes half height of 

 head, small, bare ; three distinct ocelli. IViorax oblong, a little 

 longer than broad ; scutellum large, semicircular. Abdomen as 

 broad as thorax, comparatively short, egg-shaped or cvlindrical, 

 obtuse at tip, with some fine long hair on venter and at apex ; 

 genitalia in both sexes sometimes hidden, in some species 

 prominent in J, \vith two globular knobs; in other?, tlie ovi- 

 positor in the $ lies in a groove. Legs comparatively weak, of 

 moderate length, hind pair barely longer. Wings in rest parallel, 

 lying against the sides of the body ; thoracal squamos very large, 

 bare. 



Range. Europe, Asia, Africa, America, Australia. 



Life-histofii. Larva cylindrical, narrower anteriorlv, convex 

 above, flat below ; 1st segment small and very short, mouth-hooks 

 large, directed downwards ; antenna? short, blunt, cuticular, wide 

 apart at base, with two apical, ocellus-like, chitinous rings; body 

 with two rows of tubercles on each side. The eggs or youuf* 

 larva; are laid in the nostrils of sheep, goats, or antelopes ; the 

 larvae develo|) in the frontal sinuses, and when fully developed 

 they fall to the ground and jiupate under stones or in crevices in 

 the earth. 



The perfect insects are moderate sized and nearly bare, with 

 silvery-white retiections and black or dark coloured i)imple-like 

 spots that give them a pied or spotted appearance. They are 

 extremely inert and settle freely on walls in proximily to slieej)- 

 stalls, whence they are easily captured by hand. 



304. (Estrus ovis, L. 



(Jislrus ovin, Linn;eus, Faun. Siiec, 2nd ed. p. J 7.34 (17(31). 

 lEsfrus ofijiii.'!, Fischer, Diss. Observ. do (]'].><tro, J>eipz. iii, iil. -J, lit>s 



1-5(17«7). 

 QUatnis misdlis urinns, Nimian, Tijdskr. v. d. Vetensk. iv p 1,3;? 



pi. i, fij:.L'(I850). 

 (Kslrus orig, liraucr, Mon. (l-^slr. p. 151, i)l. iii, lio. l pi, ^ji 



fig. 10(1803). 



2c2 



