PHLEBOTOMUS 365 



slight variations in wing venation, palpal lengths, etc., thus the second 

 segment of palpi of P. papatasii is a little longer than the third one 

 while with P. perniciosus these segments are of equal lengths. In 

 P. minutus the second segment is only half the length of the third. 

 The insect lays about 40 eggs in damp dark places. The period of 

 metamorphosis from egg to insect is about one or two months, 

 according to temperature. 



Phlebotomus larvae die out in dry soil and very wet earth is un- 

 favorable. Moderate moisture and protection from light seem neces- 

 sary for their development. The remains of dead insects also seem 

 to make good breeding places. It is in cracks of old damp brick 

 or stone walls that the female most often deposits her eggs. Caves 

 are also selected. Blood seems necessary for the fertilization of the 

 eggs but lizard blood seems more common in the stomach of P. minutus 

 than human blood. They have also been observed to feed on other 

 reptilian bloods. The female insect has been kept alive in captivity 

 up to forty-six days. 



Culicidae. Mosquitoes have three main parts of the body the head, 

 the thorax, and the abdomen. On the head, the space behind the two 

 compound eyes is called the frons, in front, and the occiput posteriorly. 



The nape is back of the occiput. The bulbous prolongation of the frons which 

 projects over the attachment of the proboscis is the clypeus. The clypeus is hairy 

 in the Culex; scaly in Stegomyia. The proboscis is straight in all mosquitoes of 

 importance medically. It consists of a fleshy, scaled, gutter-shaped portion be- 

 neath, known as the labium, which terminates in two hinge-joint processes the 

 labella. At the end of the labium is a thin membrane (Button's membrane). It 

 is through this that filarial embryos are supposed to pass on their way from the 

 interior of the labium to enter the person bitten. The labium may be considered 

 as the sheath of a knife, holding and protecting the slender, blade-like penetrating 

 organs. Lying in this groove we have, from above downward, the horseshoe- 

 shaped labium -epipharynx, the undersurface of which is open. This when closed 

 by the underlying hypopharynx forms a tube through which the blood is sucked 

 up by the mosquito. In the hypopharynx, which somewhat resembles a hypoder- 

 mic needle, is a channel, the veneno-salivary duct. It is down this channel that 

 the malarial sporozoite passes. There are two pairs of mandibles and two pairs 

 of maxillae on either side of the hypopharynx the mandibles above and the maxillae 

 below. The serrations of the maxillae are coarser than those of the mandibles. 

 The sensory organs, the palps, lie on either side of and slightly above the proboscis. 

 These are of the utmost importance in differentiating mosquitoes and must not 

 be confused with the antennae, which are attached above the palpi and at the sides 

 of the clypeus. These antennae are of importance in distinguishing the sex of the 

 mosquito. 



The thorax is largely made up of the mesothorax, at the posterior margin of 



