. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. LIFE HISTORY OF PHLEBOTOMUS FLIES 469 could not penetrate. The eggs are elongate and are of a dark, shiny brown color, with fine surface markings which vary in different species (Fig. 214). The incubation in the case of the common Old World P. papatasli requires from six to nine days under favorable con- ditions, but the eggs are very susceptible to external conditions, and die quickly if ex- posed to sunUght or if not kept damp. The larvae (Fig. 212B) are tiny caterpillar-Hke creatures with a relativel
. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. LIFE HISTORY OF PHLEBOTOMUS FLIES 469 could not penetrate. The eggs are elongate and are of a dark, shiny brown color, with fine surface markings which vary in different species (Fig. 214). The incubation in the case of the common Old World P. papatasli requires from six to nine days under favorable con- ditions, but the eggs are very susceptible to external conditions, and die quickly if ex- posed to sunUght or if not kept damp. The larvae (Fig. 212B) are tiny caterpillar-Hke creatures with a relatively large head with heavy jaws (Fig. 215), and with two pairs of bristles on the last segment of the abdo- men, one pair of which are sometimes nearly as long as the body and are held erect and y^ spread out fanlike; in the newly hatched fiq, 214. Eggs of larvae there is only one pair of bristles. The ptiebotomus flies; A, p. , , . • 1 1 -ji ,.11 pavatasii; B, P. argen- body IS provided with numerous toothed tipes; c, P. minutus. spines which give it a rough appearance, x about 200. (After These spines have recently been shown by ""^^ • Howlett to differ in different species and, together with the rela- tive length of the caudal bristles, to form good identification marks. The whole length of the larva of P papatasii when full grown is less than one-fifth of an inch, and is therefore not so large as an ordinary rice grain. It is quite active in spite of the fact that it has neither legs nor eyes; it progresses in the manner of a caterpillar, holding to a rock or board with the tip of the abdomen while stretching the body, then hiding with the doubled-under head while drawing up the body again. It feeds on belToiPhleZ^tZlrrinu- decaying vegetable matter, and probably tus larva. Much enlarged, also on moulds, etc. When exposed to (After Howlett.) j.^,j^^ ^^^ j^^^^ ^^ p papatosU has the peculiar habit of flicking itself off the surface on which it has been resting. On
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