GASTuopniLUs. 399 



Eui-ope, North Africa, Xorth America and at the Cape of Good 

 Hope. 



Life-history. Larva 11-segineuted, all except the last two seg- 

 ments with a double row of liorny bristles. The $ imago hovers 

 almost perpendicularly in the air, and barely settles as she deposits 

 an egg on one of the hairs of the host, to which it adheres. Four 

 to five hundred eggs are known to have been deposited on a single 

 horse, generally inside the knee or on the fetlocks, but alwavs 

 only on those parts of the body that the horse can reach to lick. 

 After four or five days on the hairs, the slightest application of 

 heat and moisture is sufficient to cause the larva to emerge*. 

 When transferred by the animal's tongue to the mouth and thence 

 to the stomach, they affix themselves to the inner membrane 

 by two small hooks, and are believed to feed on the secretions 

 caused by their presence, A hundred have been found in a 

 single horse. 



Form bengalensis, Macquart. 



I can i)erceive no difference between the Indian examples 

 described above, aud typical eqid in the British Museum and from 

 other sources, except that the colour is generally ])aler yellow. 

 Macqnart's only two specific characters (of bengalensis), " 3rd 

 antennal joint brown '' and " abdomen without dorsal spots," are 

 not reliable, the antenna; being variable in colour, whilst the 

 irregular rows of brownish marks, often forming bands, at the 

 bases of all the middle segments, though nearly always present and 

 very distinct in specimens with the pubescence somewhat worn, 

 are sometimes quite absent. Van der Wulp also considered 

 benr/cdensis as a synonym of equi. This pale form {bengalensis) is 

 represented in tlie British IMuseum from widely separated 

 localities: Bareilly, 19(»5 [Major E. Jennings); India (Bomba)/ 

 Nat. Hist. JSor..) ; Chaman, Kojak Pass, Afghanistan, 28. vii. ISSCi, 

 "at mess, 11 p.m." {Col. Ch. Swinhoe) ; Mesopotamia; Cy])rus ; 

 and several localities in South Africa. 



309. Gastrophilus nasalis, L. 



(Estrns nasnlis, Linmeus, Syst. Ed. Xat. x, p. 590 (17o8). 



(Kstrus veteriniis, Clark, Trans. Linn. 8oc. Lend, iii, p. 1528 (1797). 



CEstnis salutif'cni.s, Clark, Etsay on Lots, p. ;3;j, pi. i, tiog. -JQ 27, 



:};i-46(l8ir>). 



Oastrus clarJdi, Lcacli, Eprob. Ins. p. 2 (1817), and .Mem, Wern. 



Soc. ii, p. o(J8 (1818). 

 Gastrus juincntnrnm, Meij^eii, Syst. Beschr. iv, p, 179 (1824). 

 frastrus snluidrin, .Meifrcn, op. cit. p. 17(1 (1824), 

 CFMrus duDdcmilis, Schwab, Die (I'^straciden, pp. 35, .37 (1840), 

 (ra»(nts nif/rifi(!i, Zettcrstedt, Dipt. Scand. iii, p !)S1 (1844). 

 Gastrus aubjacens, Walker, List Dipt, Brit. Mus. iii, p. tl87 (1849). 



* Even tlic moistened palm of tiio hand is, arcordiiig (o Ciark, siiflii-iciit to 

 liatch tlieui easily. 



