148 The Philippine Journal of Science 1923 



placed at about the middle. Eggs are deposited on the lower 

 portions of the legs, principally between the toes and at the heel 

 under the dew claws, less commonly up as high as the knee. 



Hatching.— The young larva emerges from the egg by cutting 

 a small circular flap on the dorsal surface of the anterior end 

 of the egg (Plate 2, fig. 5). The incubation period varies con- 

 siderably, possibly dependent upon certain stimuli which the 

 egg may receive under conditions favorable for the young larva 

 to become established in the host. Under laboratory conditions 

 eggs hatched in from three to five days. 



Young larva.— The young larvae emerge from the egg headed 

 toward the base of the hair. They work their way down the 

 hair and then down the leg to the coronary band. Whether 

 they attempt to enter the flesh at places other than that of the 

 region of the coronary band is not known, but the presumption 

 is that such is the case. In two cases, foot maggots have been 

 found infesting regions other than that of the coronary band. 

 Both of these were goats, animals whose skin is comparatively 

 thin and tender. In these animals, both the coronary region 

 and the knee were infested. In all other cases only the coro- 

 nary region was involved. In all of the host animals, the ten- 

 derest part of the leg is the bulb of the heel, and the heaviest 

 infestations are always found there. From these facts and 

 from observations on newly hatched larvae it seems safe to say 

 that the larvae attempt to enter the flesh at the point at which 

 they happen to be when hatched, or they wander around search- 

 ing until they find a place to enter or are brushed off or die. 

 Because of the softness of the tissue of the coronary region, 

 especially around the heel, the larva* that survive and reach 

 that region are able to enter and bury themselves in the flesh. 

 Evidently the young larvae enter the flesh before the third pair 

 of slits is formed on the posterior stigmal plates, for no speci- 

 mens with three pairs have been observed outside the tissue of 

 the fl e°s t n and """^ ^ ^^ bUt tW ° PalrS haVe been dug ° ut ° f 

 The maggots bury themselves in the tissue nearlv parallel to 

 the surface, leaving their posterior end exposed. The entrance 

 holes are simple and small (Plate 7, figs. 1, 3, and 4), and once 

 extent ^ ^^ d ° ^ m ° Ve ar ° Und to any a PP reciable 



Full-gr 0W n larva.-The length of the larval period is not defi- 

 n^wT' Fr °T CaSe hiSt ° ries and infestations, it ap- 

 pears that the period probably ranges from two to three weeks. 



1 



