Mosquitoes and Malarial Fever 543 



2. Abdominal scales narrow, curved or spindle 



shaped, in tufts and dorsal patches. . . Nyssorrhynchus. 



3. Abdomen almost completely covered with 



scales and also having lateral tufts .... Cellia. 



4. Abdomen completely scaled ............. Aldrichia. 



Species of the genera Anopheles, Myzomyia, and Myzorrhynchus, are 

 known to transmit malarial parasites. The culicinae include Stegomyia 

 and Culex, which have some medical interest, as the former transmits 

 yellow fever; the latter, filarial worms. 



I. Posterior cross-vein nearer the base of the 



wing than the mid-cross-vein. 

 i . Proboscis curved in the female ........ Psorophora. 



2. Proboscis straight in the female: 



A. Palpi with three segments in the 



female. 



a. Third segment somewhat 



longer than the first two . . Culex. 



b. The three segments are equal 



in length ................ Stegomyia. 



B. Palpi with four segments in the 



female. 



a. Palpi shorter than the third 



of the proboscis. Spotted 



wings ................... Theobaldia. 



b. Palpi longer than the third of 



the proboscis. Irregular 



scales on the wings ....... Mansonia. 



C. Palpi with fine segments in the 



female ............. .......... Taniorrhynchus. 



II. Posterior cross- vein in line with the mid-cross- 



vein ................................. Joblotina. 



III. Posterior cross-vein further from the base of 



the wing than the mid-cross-vein ...... Mucidus. 



The mosquitoes used for study and for classification 

 should be mounted dry in the usual way well known to all 

 entomologists. Fine entomologic pins (oo-ooo) should be 

 employed for the purpose. The insects should be caught in 

 a wide-mouth bottle containing some fragments of cyanid of 

 potassium, covered with a layer of saw-dust, over which a 

 thin layer of plaster of Paris is allowed to solidify. The 

 insects die in a moment or two, can be emptied upon a table, 

 and the pin carefully thrust through the central part of the 

 thorax. As soon as the insect is impaled, the pin should be 

 passed through an opening in a card or between the blades of 

 a forceps until the insect occupies a position at the junction 

 of the middle and upper third. The insect should not be 

 touched with the fingers, as the scales will be brushed off and 

 the limbs broken. Mounted insects must be handled with 



